Solar Air-to-Fuel Technologies for a Circular Carbon Economy Sayan Kar* and Erwin Reisner* Cite This: J. Am. Chem. Soc. 2026, 148, 10267−10285 Read Online ACCESS Metrics & More Article Recommendations ABSTRACT: The CO2 present in our atmosphere is a universally available and abundant carbon feedstock, but it exists only in dilute concentrations (currently around 427 ppm). Clean technologies capable of capturing atmospheric CO2 using direct air capture and directly converting it into synthetic fuels and chemicals using solar energy could pave the way for a circular chemical industry. Challenges in developing such a solar-powered air-to-fuel technology that mimics photosynthesis include the use of the low CO2 concentration in air, the thermodynamic stability of CO2 (and its capture products), the high O2 content (21%) in air (which often interferes with catalytic CO2 valorization), and the presence of variable moisture levels. This perspective explores different concepts and emerging technologies for the solar-powered conversion of atmospheric CO2 into fuels and chemicals, examines their scientific principles, considers their scalability, and offers recommendations for future research to support the development of a net-zero circular carbon economy. 1. INTRODUCTION Earth’s natural carbon cycle plays a crucial role in sustaining life on our planet. Until the industrial revolution, the atmospheric carbon dioxide (CO2) levels had largely remained stable (at below 300 ppm) for several thousand years, with forests, soil, and oceans sequestering nearly equal amounts of CO2 to those being released by the natural processes (Figure 1).1,2 Since the industrialization of our planet over the past 250 years, vast quantities of additional CO2 have been and continue to be released into the atmosphere by using the planet’s fossil fuel reserves to meet the energy demands of our civilization.3 This additional anthropogenic CO2 emission (currently at 30−40 billion tons per year) is causing a carbon cycle imbalance. Consequently, atmospheric CO2 levels continue to rise, and while its effects in the form of global warming, climate change, ecological destabilization, ocean acidification, and others have long been predicted, they are now beginning to have a profound impact on our planet.4−7 To address this, significant attention is being devoted to reducing net CO2 emissions on a global scale.8 In devising future solutions, it is essential to recognize our reliance on carbon; as all life is composed of carbon, our economy runs on carbon, and our everyday materials largely depend on carbon. Anthropogenic carbon circularity can be achieved through a nature-inspired approach, where we develop efficient ways to capture and manipulate CO2 from the air for everyday fuel and chemical synthesis.9,10 This air-to-fuel approach will not only enable us to recycle or reduce atmospheric CO2 but also minimize our reliance on fossilized carbon.11−14 Aerobic utilization of CO2 to produce fuels enables an anthropogenic net-zero carbon cycle, where CO2 is reemitted into the atmosphere when the recycled fuel is used, closing the loop. Alternatively, aerobic CO2 fixation into long-lasting chemicals, such as polymers, yields a carbon- negative cycle but is constrained by the limited amount of polymer required in human society.15,16 Another related carbon- negative approach is the capture and subsequent storage of atmospheric CO2 in geological formations, as in direct air carbon capture and storage (DACCS); however, the safety, prudence, and economic viability of storing gigatons of pressurized CO2 underground remain the subject of considerable debate.17−20 Among the ways to harness and chemically valorize CO2 directly from air, the direct solar-powered route is ambitious but arguably the most promising long-term solution due to the abundance and the low cost of solar energy.21,22 As in natural photosynthesis, solar-powered air-to-fuel technologies aim to produce energy-rich carbon-based fuels directly from atmos- pheric CO2, utilizing sunlight as the energy source (Figure 1).23−25 This approach offers several benefits: (i) it utilizes atmospheric CO2 directly instead of relying on localized concentrated streams, (ii) it employs sunlight as a clean, emission-free, and abundant energy source,26 and (iii) it creates value by synthesizing targeted fuels and chemicals tailored to our needs instead of solely storing CO2 in the ground,27 as envisaged by conventional DACCS.19,20 Considerations regarding the required efficiency and scalability make solar air-to-fuel conversion a formidable challenge. While nature has been carrying out this process for millions of years using photo- synthetic organisms,28 artificial systems for the process have only recenly been explored and are at an early formative stage. These recent developments will be covered in this perspective. Received: December 5, 2025 Revised: January 27, 2026 Accepted: February 17, 2026 Published: March 4, 2026 Perspectivepubs.acs.org/JACS © 2026 The Authors. Published by American Chemical Society 10267 https://doi.org/10.1021/jacs.5c21750 J. Am. Chem. Soc. 2026, 148, 10267−10285 This article is licensed under CC-BY 4.0 https://pubs.acs.org/action/doSearch?field1=Contrib&text1="Sayan+Kar"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdf https://pubs.acs.org/action/doSearch?field1=Contrib&text1="Erwin+Reisner"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdf https://pubs.acs.org/action/showCitFormats?doi=10.1021/jacs.5c21750&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?goto=articleMetrics&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?goto=recommendations&?ref=pdf https://pubs.acs.org/toc/jacsat/148/10?ref=pdf https://pubs.acs.org/toc/jacsat/148/10?ref=pdf https://pubs.acs.org/toc/jacsat/148/10?ref=pdf https://pubs.acs.org/toc/jacsat/148/10?ref=pdf pubs.acs.org/JACS?ref=pdf https://pubs.acs.org?ref=pdf https://pubs.acs.org?ref=pdf https://doi.org/10.1021/jacs.5c21750?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://pubs.acs.org/JACS?ref=pdf https://pubs.acs.org/JACS?ref=pdf https://creativecommons.org/licenses/by/4.0/ 2. CHALLENGES 2.1. Ultradilute CO2 Concentration One key challenge in working with atmospheric CO2 is its low concentration in air, currently around 427 ppm (Figure 2a). Thermodynamically, it requires approximately 19.2 kJ molCO2 −1 , corresponding to 0.44 GJ tonCO2 −1 , to concentrate ambient CO2 from atmospheric levels to pure CO2 at 1 bar (at temperature 25 °C) , which most solar utilization technologies would use as feedstock to avoid slow reaction kinetics arising from otherwise low substrate availability and slow mass transport (Figure 2b). Taking into account suitable kinetics, heat losses, efficiency losses, and the energy needed for air intake, current direct air capture (DAC) systems consume in reality between 5 and 9 GJ tonCO2 −1 .29 The majority of DAC technologies operate through chemical CO2 capture, where CO2 is first captured (absorbed or adsorbed) chemically and then extracted as a concentrated stream using a temperature or pressure swing.30 The low CO2 concentration in air necessitates capturing agents with high CO2 fixation rates (lowest activation energy) for suitable kinetics that are often associated with greater thermodynamic stability of the captured CO2 (Figure 2b), making subsequent release energy- intensive. Typical DAC materials utilize ethanolamines, specialized amines, or hydroxide-based agents as the active components,30,31 with extensive material development ongoing to create improved energy-efficient DAC chemical systems with faster reaction kinetics and lower thermodynamic energy penalty.32−35 Beyond thermal processes, innovative DAC methods powered by alternative energy sources are also being explored. These include hybrid electrochemical DAC systems with electrochemically active redox species for reversible CO2 capture,36−38 electrochemically mediated amine regeneration techniques via the competitive binding of a redox-active metal ion with amines,39−42 moisture swing DAC adsorbents for regeneration through a humidity alteration in the feed gas,43−45 electrochemically or photochemically triggered pH swings for reversible CO2 capture and release,46−49 and membrane-based CO2 separation from air.50,51 Comprehensive analyses of these systems have recently been undertaken.52−54 These emerging technologies are in early stages and require further development before they can be used in DAC facilities. CO2 from air can also be used directly for conversion without prior concentration to avoid the DAC energy penalty, but the low CO2 concentration makes the reaction kinetics in such systems sluggish.55 This is often exacerbated by interference from other high-concentration reactive species in the air such as oxygen and moisture. 2.2. High Oxygen (O2) Content The O2 concentration in the atmosphere is 21%, approximately 500 times that of CO2. Unlike the most abundant and mostly inert gas in the atmosphere, nitrogen (N2; 79%), O2 is a reactive diradical that can interfere with the CO2 conversion process. The facile nature of the oxygen reduction reaction is reflected in its positive and thus favorable reduction potential (to OH−, H2O2,, or H2O), compared to CO2 reduction reactions.57 Nature has addressed this problem in photosynthesis by developing the ribulose-1,5-bisphosphate carboxylase/oxygen- ase (RuBisCO) enzyme, which is several orders (∼103) more active in reducing CO2 than O2 (Figure 2c). 58,59 Several factors, including high active-site affinity, enhanced local solubility, and stabilizing side-chain interactions, contribute to RuBisCO’s preference for reducing CO2 over O2, which nature has refined over millions of years.60,61 Even so, for plants lacking a local CO2 concentration mechanism where CO2 is uptaken through the leaf stomate and directly relayed to RuBisCO in mesophyll cells (C3 plants), RuBisCO is known to reduce, on average, one O2 molecule (photorespiration, hence the term oxygenase in its name) for every three molecules of CO2 (photosynthesis), reducing the overall photosynthesis efficiency by approximately 25% (Figure 2d).62,63 Figure 1.The net zero carbon cycle of the future. The natural circular carbon cycle is illustrated on the left, showing different carbon fluxes to and from air (nonexhaustive), including those from natural activities (1), forests (2), rainfall (3), topsoil (4), animals (5), and oceans (6). All natural fluxes combine to a total CO2 emission of around zero. Flux 7 represents the anthropogenic CO2 emission that currently enters the air without removal. The top-right corner illustrates the envisioned anthropogenic circular carbon cycle (8) through solar CO2 recycling into fuels from air for a circular carbon economy. Journal of the American Chemical Society pubs.acs.org/JACS Perspective https://doi.org/10.1021/jacs.5c21750 J. Am. Chem. Soc. 2026, 148, 10267−10285 10268 https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig1&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig1&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig1&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig1&ref=pdf pubs.acs.org/JACS?ref=pdf https://doi.org/10.1021/jacs.5c21750?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as 2.3. Nature’s CO2 Concentrating Mechanisms Selectivity for CO2 reduction is enhanced in nature through a preconcentration mechanism in C4 plants, where atmospheric CO2 is initially fixed as part of a four-carbon compound within mesophyll cells and then released in the bundle sheath cells at higher concentrations around RuBisCO, where the Calvin cycle Figure 2.Challenges in CO2 reduction from air and nature’s solutions. (a) The challenges and various approaches, (b) the thermodynamic and kinetic considerations (Ea, ΔGabs, and Qmin refer to the activation energy, free energy change during CO2 absorption, and minimum work for release to 1 atm CO2, respectively), and (c) natural atmospheric CO2 fixation during photosynthesis enabled by the RuBisCO enzyme. The RuBisCO structure is taken from the National Institutes of Health database and is available in the public domain.56 (d−g) Various CO2-relaying and concentrating mechanisms observed in nature to deliver atmospheric CO2 to RuBisCO, including in C3 plants (d), C4 plants (e), CAM plants (f), and cyanobacteria (g) (CA denotes carbonic anhydrase). Journal of the American Chemical Society pubs.acs.org/JACS Perspective https://doi.org/10.1021/jacs.5c21750 J. Am. Chem. Soc. 2026, 148, 10267−10285 10269 https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig2&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig2&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig2&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig2&ref=pdf pubs.acs.org/JACS?ref=pdf https://doi.org/10.1021/jacs.5c21750?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as (dark reactions) takes place (Figure 2e).64,65 Alternate ways to improve CO2 reduction selectivity, as seen in nature, include temporal separation of CO2 uptake and reduction, as in CAM (Crassulacean Acid Metabolism) plants, where CO2 is stored overnight and released for reduction during the day (Figure 2f),66,67 or the local release of concentrated CO2 via pH swing within microcompartments called carboxysomes found in cyanobacteria. Carboxysomes contain the enzymes carbonic anhydrase and RuBisCO close to each other, where carbonic anhydrase facilitates the local concentrated CO2 release, and RuBisCO fixes the released CO2 in situ (Figure 2g).68,69 Devising synthetic methods to achieve a similar competitive advantage in CO2 reduction in the presence of 21% O2 has proved challenging, with prominent approaches being surface hydrophobic treatment, catalytic molecular tuning, and introduction of CO2 transport relays to active sites, among others.57,70−72 2.4. Temporal Decoupling of Capture and Reduction A nature-inspired strategy to avoid O2 interference has been the temporal decoupling of the CO2 capture and conversion processes into separate steps, as in CAM plants, rather than simultaneous capture and conversion (Figure 3).73,74 The common chemicals used in CO2 capture (including DAC), such as amines, ethanolamines, and hydroxides, are unreactive toward Figure 3.Direct and stepwise air capture and conversion. The direct route consists of direct CO2 conversion at lowCO2 concentrations in the presence of O2. In the stepwise approach, CO2 is first captured or separated from N2 and O2, followed by its conversion. Figure 4. Solar−thermal air-to-fuel systems. (a) CeO2-based thermochemical cycle, (b) the solar−thermal air-to-fuel technology with three distinct steps89 (the red and blue ceria reactors represent the “hot” (1500 °C) and “cold” (900 °C) chambers, respectively), (c) the direct air capture system using immobilized amines,90 and (d) solar−thermal air-to-fuel technology using dual functional materials for CO2 capture and conversion.97 Journal of the American Chemical Society pubs.acs.org/JACS Perspective https://doi.org/10.1021/jacs.5c21750 J. Am. Chem. Soc. 2026, 148, 10267−10285 10270 https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig3&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig3&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig3&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig3&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig4&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig4&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig4&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig4&ref=pdf pubs.acs.org/JACS?ref=pdf https://doi.org/10.1021/jacs.5c21750?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as nonelectrophilic O2. Thus, CO2 can be selectively separated and captured in the solution by these chemicals while allowing other gases, such as N2 and O2, to pass through. The CO2-loaded solution can then release pure CO2 gas using solar power. Such a decoupled system can operate throughout the full diurnal cycle, using night-time to concentrate aerobic CO2 in solution and day-time for the release and conversion of pure CO2. 75 2.5. Presence of Moisture and Other Impurities Complications can arise from the presence of moisture in air, which fluctuates throughout the diurnal cycle. For physisorbing DAC materials based on porous, ordered structures (zeolites, metal−organic frameworks), humidity can substantially reduce their CO2 capture performance due to competitive binding within the pores.76 Conversely, chemisorbing DAC materials (especially amine-based ones) exhibit improved CO2 capture rates and capacities in humid conditions, but coadsorption of water increases the energy intensity of desorption while decreasing the purity and recovery rate of CO2. 77−79 The presence of moisture in the recovered CO2 can further interfere with its downstream conversion, often necessitating additional CO2 drying or moisture-stabilizing steps. In addition, in many electro- and photo-catalytic CO2 utilization processes, some moisture is required to supply the protons needed for the CO2- reduction chemistry to proceed. Besides O2 and moisture, other impurities present in air, such as NOx and SOx, can potentially interfere with DAC or conversion, but their aerobic concentration is typically low enough (parts per billion levels) to avoid any prominent effect. This contrasts with CO2 capture and utilization from dilute industry sources such as postcombustion flue gases where elevated SOx and NOx levels are commonly observed (100− 1000 ppm).72,80 3. STATUS Several innovations have been reported recently for the direct synthesis of fuels and chemicals from atmospheric CO2, with sunlight serving as the primary energy source. These technologies utilize various approaches, including physical, chemical, and biological CO2 fixation, combined with thermochemical, electrochemical, photochemical, and biochem- ical conversion pathways to achieve solar air-to-fuel synthesis, as detailed below. 3.1. The Solar−Thermochemical Pathway 3.1.1. Thermochemical Looping. CO2 can be split into CO and O2 at high temperatures via a thermochemical cycle using oxygen-transport materials, such as ceria (CeO2) (Figure 4a).81,82 CeO2, when treated at high temperatures (above 1000 °C), releases O2 from its structure to form reduced oxygen- vacant ceria (CeO2−δ, δ up to 0.04). Reduced CeO2, when exposed to CO2 or H2O at a lower temperature (<1000 °C), extracts oxygen from these feedstocks to fill its oxygen vacancy while producing carbon monoxide (CO) and hydrogen (H2), respectively. Besides CeO2, other oxygen-transport materials can also be used to split H2O and CO2 at high temperatures, including zinc oxide, metal-doped iron oxides, iron−aluminum oxides, and perovskite materials.83−87 The material must maintain a stable lattice structure at the required high temperatures (∼1500 °C) under repeated heating and cooling cycles for a prolonged period to be effective for continuous operation. The process can be solar-driven when concentrated sunlight is used to achieve high temperatures. When sunlight is used directly to heat the transport material, it is termed direct thermochemical splitting. Conversely, if concentrated solar heat is transferred via a heat-transfer liquid, it is termed an indirect process.88 Most high-temperature CO2 splitting reports based on thermochemical looping using oxygen-transport materials have focused on using prepurified concentrated CO2. Recently, Steinfeld and co-workers have demonstrated its integration with direct air CO2 capture to produce drop-in fuels from sunlight and air (Figure 4b).89 In the first step, CO2 and moisture are captured from the air using well-established solid amine-based adsorbents developed by the same group in the early 2010s (now pursued through the spin-off company Climeworks).90,91 These adsorbents release captured CO2 at moderate temperatures (80−100 °C) or under reduced pressures (Figure 4c). In the developed technology, air-captured CO2 is released under mild heat (100 °C, obtained fromwaste heat of the solar refinery, vide infra) at reduced pressure (<0.1 bar) and fed to a solar refinery at ambient pressure, where the second step, conversion to syngas (a mixture of CO and H2, which is an industrial fuel and chemical precursor), takes place. The solar refinery employs porous CeO2 blocks, which are initially heated to 1500 °C using highly concentrated solar light (intensities of up to 3000−5000 kW m−2, equivalent to 3000− 5000 suns) via a parabolic dish collector (Figure 4b).92 This step, also known as the reduction or oxygen-release step, is performed under reduced pressure (0.1mbar) to maximize oxygen vacancies in reduced ceria. In the subsequent oxidation or oxygen-uptake step, concentrated sunlight is moved away from the block, allowing it to cool down. Air-captured CO2 and H2O are then introduced at ambient pressure, around 900 °C, to complete the thermochemical cycle by restoring the oxygen atoms to ceria while producing syngas (Figure 4a). The porosity of the ceria block plays a crucial role and is tuned to balance two opposing factors: an increase in solar absorption with larger pore sizes, and an increase in reaction rate with smaller pore sizes due to an increase in the surface area of the block.88,93 The regenerated CeO2 is reused in the next thermochemical cycle. This process can produce approximately 4 L of syngas per kilogram of CeO2 per cycle, demonstrated for a few hundred cycles, with a recorded solar-to-syngas efficiency of around 3− 5%.89 The produced syngas can be utilized to produce liquid fuels in a downstream gas-to-liquid (GTL) unit, such as to methanol (marine fuel) using an industrially established Cu/ ZnO/Al2O3 syngas-to-methanol catalyst or to kerosene (aviation fuel) via Fischer−Tropsch synthesis.89 The GTL conversions are typically conducted at around 200−300 °C by using waste heat from the solar refinery, making the process entirely solar-driven. The overall system efficiency of this air-to- fuel process was estimated to be around 1%. It has been scaled to 50 kW (∼50 m2 of solar irradiance) at IMDEA Energy in Spain for CO2-to-fuel production, albeit without the DAC component, and material stability over long reaction times poses a challenge.94 Other challenges include high capital expenditure requirements (for heliostat field), need for large amounts of porous CeO2 (critical mineral) and quartz, high radiative heat loss during operation, nonstoichiometric oxygen transfer, and material sintering at elevated temperatures, which reduce efficiency and longevity.95,96 3.1.2. Solar Thermal Catalysis Using Dual Sorbent Materials. Besides thermochemical looping, dual-functional catalytic sorbents can also be used for DAC and its subsequent conversion to synthesis gas under concentrated sunlight (Figure 4d), as reported recently by Liu and co-workers.97 Unlike the Journal of the American Chemical Society pubs.acs.org/JACS Perspective https://doi.org/10.1021/jacs.5c21750 J. Am. Chem. Soc. 2026, 148, 10267−10285 10271 pubs.acs.org/JACS?ref=pdf https://doi.org/10.1021/jacs.5c21750?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as thermochemical looping systems, where CO2 capture and utilization occur at separate locations with different materials, here the sorbent plays roles in both CO2 capture and conversion. The adsorbent consists of a commercial zeolite, NaA, which aids in CO2 capture, and is impregnated with nickel, which facilitates CO2 conversion. In a typical reaction setup, a CO2-containing gas (including simulated air) is first passed through the adsorbent at ambient temperature for preloading of CO2 (up to around 1 mmol per gram of the adsorbent). The adsorbent is then exposed to concentrated sunlight (around 410 sun intensity, 410.2 kWm−2) under CH4 flow, resulting in adsorbed CO2 release and its conversion to synthesis gas via dry methane reforming process with reaction temperatures reaching 700 °C under concentrated light illumination. CO2 conversion of up to 95% is reported under these conditions. However, using the same material as both the capture sorbent and the conversion catalyst limits the scale of the single-cycle reaction due to limited CO2 adsorption. Continuous switching between capture and conversion required for continuous operation can also be challenging. 3.2. The Photovoltaic-Driven Electrochemical Pathway CO2 can also be recycled into fuels and chemicals using electrical energy, with or without the aid of high temperatures.98,99 High- temperature (typically operating above 500 °C) solid oxide electrolysis cells (SOECs) have been intensively investigated for CO2-to-fuel conversion and have been reviewed recently.100−102 The integration of SOECs with DAC systems has recently been envisioned.103 This process can be solar-driven if the required electricity and heat are generated with photovoltaic panels and concentrated solar thermal power, respectively. Electrochemical systems can also reduce CO2 without high temperatures and, consequently, without the thermodynamic Carnot losses. The reduction of pure CO2 using near-ambient-temperature electro- lyzers has advanced rapidly in recent years, with current densities reaching A cm−2 levels.104−106 However, the electrochemical conversion of CO2 directly from air remains challenging due to low CO2 and high O2 concentrations (Figure 5a). 3.2.1. Electrochemical Systems without Photovoltaic Integration. 3.2.1.1. Direct Electroreduction from Atmos- pheric Concentration CO2.We have recently reported a nature- inspired approach for CO2 capture and electroreduction from atmospheric concentrations, utilizing a local carbon-concen- tration mechanism involving carboxysome-type microconfined structures, as found naturally in cyanobacteria (Figure 2g). Similar to cyanobacteria, where carbonic anhydrase (CA) and RuBisCO are colocated within a carboxysome, we immobilized carbonic anhydrase and the CO2 reductase formate dehydrogen- Figure 5. Photovoltaic-driven electrochemical air-to-fuel systems. (a) Photovoltaic (PV)-driven electrolysis directly from air (Red denotes the reductant, Pox denotes the oxidized product), (b) carboxysome-inspired semiartificial approach where carbonic anhydrase (CA) converts bicarbonate to CO2 for formate dehydrogenase (FDH) inside electrode pores to produce formate from air,107 (c) stepwise approach for electrolysis of air-captured CO2 solutions using bipolar membranes (BPM) for local CO2 release, 74,108 (d) direct carbonate or carbamate electrolysis with a CO2 diffusion layer (CDL) for CO2 transport to the cathode109 (CEM denotes the cation exchange membrane), and (e) the buried junction photoelectrochemical system operating directly by sunlight under external bias-free conditions73 (VOC, EG, and GA denote the open-circuit voltage, ethylene glycol, and glycolic acid, respectively). Journal of the American Chemical Society pubs.acs.org/JACS Perspective https://doi.org/10.1021/jacs.5c21750 J. Am. Chem. Soc. 2026, 148, 10267−10285 10272 https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig5&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig5&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig5&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig5&ref=pdf pubs.acs.org/JACS?ref=pdf https://doi.org/10.1021/jacs.5c21750?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as ase (FDH) enzymes next to each other within the pores of a mesoporous indium−tin oxide (ITO) electrode (Figure 5b).107 During electrolysis in pH ranges 7−8, CA facilitates the local release of gaseous CO2 from dissolved bicarbonate, which is then consumed by FDH as a substrate to produce formate. This strategy to maximize the local CO2 concentration is particularly promising for low atmospheric CO2 concentrations due to the linear Michaelis−Menten-type kinetics observed with enzymes under low substrate conditions, resulting in a 4−8-fold increase in FDH activity for formate production.110 A >90% Faradaic efficiency for formate production at −0.6 V vs the standard hydrogen electrode (SHE)was observed, but the current density was low (∼60 μA cm−2). Further, the system is oxygen-sensitive due to the observed oxygen reduction reaction under aerobic conditions, a major challenge for direct aerobic CO2 reduction.111 3.2.1.2. Electroreduction of Chemically Captured Aerobic CO2. A promising alternative to direct CO2 electroreduction from air involves capturing the aerobic CO2 in solution first, followed by its electrolysis (Figure 5c).72,112,113 Chemical carbon capture using active chemical agents, such as amines, metal hydroxides, and amino acid salts, is an effective method for storing CO2 in solution while separating it from O2 and N2 (Scheme 1 and Figure 3). The Sargent group reported an electrolyzer system that can directly reduce carbonate electro- lyte into synthesis gas, using silver-based catalysts.74 This approach used a bipolar membrane-based electrolyzer where membrane-generated local protons during electrolysis migrated to the cathode, resulting in local CO2 release from carbonate with subsequent reduction (Figure 5c). Following this strategy, syngas at a 3:1 H2/CO ratio was produced by direct carbonate electrolysis without any gaseous CO2 contamination, achieving current densities of 150 mA cm−2 (energy efficiency ∼30%). However, the required cell potential was high (3.8 V) due to the use of a bipolar membrane and the thermodynamic stability of carbonate salts, and no carbon conversion efficiency (yield of CO produced from CO2 supplied) was reported (vide infra for a note on carbon efficiency on captured CO2 electrolysis). The cell voltage can be reduced slightly (∼3.3 V at 100 mA cm−2) by replacing the bipolar membrane with a cation exchange membrane (CEM) and using a composite CO2 diffusion layer (CDL) between the cathode and CEM to facilitate CO2 transport from the membrane to the cathode (Figure 5d).109 Along similar lines, Breugelmans and co-workers reported a bipolar membrane-based zero-gap flow electrolyzer for the electroreduction of direct air-captured (bi)carbonate solutions into formate or CO using tin oxide or silver nanoparticle- dispersed carbon electrodes (SnO2/C or Ag/C, respectively).114 Current densities of around 50 mA cm−2 were observed at a cell voltage of around 3.5 V, with Faradaic efficiencies for formate or CO production of around 15%. In addition to one-carbon products, multicarbon products such as ethylene can be produced by bipolar membrane-based carbonate electrolysis systems using copper−silver electrodes,108 where silver facilitates CO2 to CO conversion, and copper induces multicarbon product formation from CO-type intermedi- ates.115−118 At a cell voltage of 3.8 V, a carbonate-to-ethylene Faradaic efficiency of 10% was achieved with a carbonate-to- ethylene conversion efficiency of 0.002−0.003%. Besides silver- based catalysts, a copper and cobalt phthalocyanine (CoPc) composite catalyst (Cu/CoPc-CNT, CNT being carbon nanotubes) deposited on carbon paper has also been demonstrated for efficient C2 product formation from carbonate solution electrolysis, with ethylene and ethanol being the main observed products.119 Given that alkali (bi)carbonate is one of the most stable chemical species formed via CO2 capture, alternative amino- acid-based electrolytes have also been developed for the capture and direct electrochemical reduction of atmospheric CO2. 120 These systems employ amino acids with basic side chains, such as lysine, arginine, or deprotonated amino acids, such as potassium glycinate (Scheme 1), to capture aerobic CO2, followed by the electrochemical reduction of captured CO2 using a Zeolitic Imidazolium Framework (ZIF)-8 based nickel single-atom catalyst. Instead of a bipolar membrane, the reported electrolyzer used a simple cation-exchange membrane, producing CO from captured CO2 with >50% Faradaic efficiency at a cell voltage of around 3 V and consuming about 30% less energy than alkali hydroxide-based systems.120 Apart from the electrochemical, electro-thermochemical hybrid devices are also reported for CO2 concentration and conversion to CH4 from air, albeit without solar integration.121 The carbon conversion efficiency, defined as the fraction of starting CO2/(bi)carbonate molecules converted to reduction products (CO, C2H4, etc.), is an important but often overlooked parameter in direct (bi)carbonate/carbamate electrolysis.122 The few studies reporting carbon conversion efficiency indicate that only traces of captured carbon are converted to fuel. The difficulty in carbonate reduction increases with increasing carbon conversion (when the base is regenerated as part of the reaction) as in situ release of gaseous CO2 from the remaining carbonate-depleting electrolyte becomes increasingly difficult.73,108 Consequently, currents, voltages, and energy and Faradaic efficiencies are expected to falter significantly during the course of the reaction when the carbon conversion efficiency increases, which is of industrial relevance and has not yet been Scheme 1. CO2 Capture by Different Chemicals with the Chemical Species Formed Journal of the American Chemical Society pubs.acs.org/JACS Perspective https://doi.org/10.1021/jacs.5c21750 J. Am. Chem. Soc. 2026, 148, 10267−10285 10273 https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=sch1&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=sch1&ref=pdf pubs.acs.org/JACS?ref=pdf https://doi.org/10.1021/jacs.5c21750?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as sufficiently addressed. Similar issues persist in photocatalytic CO2 reduction, where catalytic activities are typically reported but CO2 conversion efficiencies are commonly overlooked (vide infra, Section 3.3).123,124 3.2.2. Electrochemical Systems with Demonstrated Photovoltaic Integration. Although the above-mentioned electrolyzers can, in principle, be integrated with photovoltaic- driven renewable electricity generation, this has not been specifically demonstrated. The required cell voltages for these processes (3−4 V) are too high to be efficiently generated by a single light absorber using incident sunlight, necessitating multijunction or multiple solar cells. For example, if integrated with state-of-the-art commercial silicon solar cells (providing open-circuit voltages of 0.6−0.7 V), it will require 4−5 cells connected in series to operate the electrolyzer with incident sunlight, which can make it area-intensive and inefficient. The required cell voltage can be reduced by moving from the thermodynamically demanding water oxidation (E0 = −1.23 V) as the counter-anodic reaction to waste-derived alcohol oxidation. The waste oxidation reactions can include the oxidation of glycerol from biodiesel production, ethylene glycol sourced from polyethylene terephthalate (PET) plastic waste, glucose from biomass, or many other waste sources and typically have standard oxidation potentials close to zero (E0 ∼ 0 V).125 By employing this strategy and utilizing ethylene glycol from PETwaste oxidation as the counter reaction, we have shown that aerobic CO2 can be captured and converted to syngas using even a single perovskite-based light absorber with an open-circuit voltage of 1.1 V (Figure 5e).75 The CO2 from the air is captured with a KOH solution dissolved in ethylene glycol and then used directly as an electrolyte in the next conversion step. The solar- driven reduction is performed using a buried-junction photo- cathode fabricated by integrating a perovskite solar cell with a cobalt phthalocyanine CO2-reduction catalyst deposited on multiwalled carbon nanotubes. When immersed in the air- captured CO2 solution electrolyte and irradiated with sunlight, the buried junction photocathode produced syngas without any externally applied bias for over 100 h at current densities of around ∼0.1 mA cm−2, albeit with a relatively high H2/CO ratio (20−25) while selectively oxidizing ethylene glycol to glycolic Figure 6. Photochemical solar air-to-fuel technologies. (a) Schematics of photochemical CO2 reduction (Red, Pred and Pox denote the reductant, reduction products, and oxidation products, respectively), (b) an example of a bimolecular complex for photochemical CO2 conversion from dilute streams,133 (c) extended molecular conjugates for photochemical CO2 reduction to near quantitative yield using polymer-based visible light absorbers134 (TEOA denotes triethanolamine), (d) strategy to enhance local CO2 concentration and ward off O2 through transparent polyporphyrin coating with embedded Pd(II) catalytic centers,135 (e) CO2 reduction from air using face selective hexagonal tungsten bronze materials,136 and (f) the dual-bed direct air CO2 capture and utilization technology developed by us for solar air-to-fuel synthesis75 (DAC: direct air capture, PET: polyethylene terephthalate, EG: ethylene glycol). Journal of the American Chemical Society pubs.acs.org/JACS Perspective https://doi.org/10.1021/jacs.5c21750 J. Am. Chem. Soc. 2026, 148, 10267−10285 10274 https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig6&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig6&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig6&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig6&ref=pdf pubs.acs.org/JACS?ref=pdf https://doi.org/10.1021/jacs.5c21750?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as acid at the anode in a two compartment H-cell separated by a bipolar membrane. For other dilute CO2 sources, such as simulated postcombustion flue gas with ∼15% CO2 concen- tration, a higher Faradaic efficiency for CO production (∼20%) and higher current densities (∼1−2 mA cm−2) were observed. The carbon conversion efficiency of the process was below 1%. 3.3. The Direct Photochemical Pathway CO2 can also be converted into fuels and chemicals using sunlight in a direct photochemical process, without requiring electrode wiring.126 In direct photochemical processes, sunlight is captured by a light absorber (molecular or material-based) to generate an electron−hole pair. The electron is then transferred to CO2, often facilitated by a cocatalyst, to produce CO2- reduction products, while the hole is transferred to a reductant (electron donor) to complete the redox process (Figure 6a).127 Adequate bandgap alignment and interfacing between the photosensitizer, catalysts, and substrates are necessary to enable vectorial electron and hole transfer in opposing directions to minimize recombination losses. This is often achieved by bandgap and interface engineering through various methods, including doping, structural modifications, alloying, strain engineering, heterojunction formation, cocatalyst modifications, and others.128−130 Simultaneously, the choice of the cocatalyst influences product selectivity, which also, to some degree, depends on the reaction medium. The photocatalytic reduction of CO2 using sunlight has been reviewed recently.126 Most photocatalytic CO2 reduction processes operate under con- centrated 100% CO2 conditions to ensure high substrate availability without oxygen. Direct photochemical CO2 reduction from air is considerably more challenging due to low ambient CO2 concentration and oxygen interfer- ence.55,131,132 3.3.1. CO2 Photoreduction fromDilute Concentrations in Anaerobic Concentrations. Ishitani and co-workers (and others) have designed molecular complexes through additive and coordination sphere engineering for CO2 photoconversion from dilute streams (including 0.04% CO2) under anaerobic conditions via localized CO2 capture. 133,137 In these systems, a light absorber molecule (such as ruthenium tris(bipyridyl) (Ru(bpy)3)) is typically conjugated with a CO2 conversion catalyst (such as rhenium bipyridyl tris(carbonyl)), while the reaction is carried out with a CO2 scavenger in the solution (such as triethanolamine) (Figure 6b).133 When light is irradiated onto the solution, the light-absorbing moiety is photoexcited to generate a HOMO−LUMO (electron−hole) pair. Due to suitable alignment of the energy levels (verified in prior experiments), the electron moves to the catalyst, where CO2 reduction takes place. Triethanolamine, present in solution, plays a dual role. First, it scavenges CO2 from the solution to bring it near the catalytic center via Re− O(carbonate) bond formation, ensuring local CO2 availability even at dilute concentrations. At the same time, triethanolamine also acts as a sacrificial electron donor (reductant), quenching the generated hole at the light absorber while being oxidized. Applying this chemical principle, the reduction of CO2 from dilute streams with concentrations as low as 5000 ppm (diluted in argon) has been demonstrated. This corresponds to retaining 60% of the catalytic activity compared to catalysis in pure 100% CO2, with a molecular turnover number of 150 after 5 h. A 480 nmwavelength monochromatic light was used, and the system is also active in an electrochemical setup.138 The light absorption can be extended to a broader visible region by attaching themolecular structure further to an efficient conjugated polymer-based solar absorber, such as P10, the 10- unit-long homopolymer of dibenzo[b,d]thiophene sul- fone.139,140 A recent report by Sprick and co-workers showed near-quantitative CO2 conversion to formate under photo- catalytic conditions using a similarly designed system at lowCO2 concentrations (with triethanolamine as the sacrificial electron donor), with a turnover number of around half a million under 460 nm light (Figure 6c).134 Catalytic activity under low CO2 concentrations is needed to achieve high CO2 conversion in any catalytic system but is often overlooked in photocatalytic CO2 reduction studies due to low conversion yields typically observed.141 Other reports on the developments of low- concentration CO2 reduction using molecular systems have been reviewed recently.137 It is worth noting that the molecular systems often require sacrificial electron donors (e.g., triethanolamine), which, although useful for catalytic studies to investigate the CO2 reduction half-reaction at an early stage, are not practical for large-scale implementation due to their high cost and stoichiometric consumption/decomposition.142 Further, mo- lecular systems, due to their well-defined HOMO−LUMO energy gap, often show narrow absorption bands in the solar spectrum (apart from the polymeric systems) that can limit overall efficiencies when using the full solar spectrum. The molecular systems described above are effective for photo- catalytic low-concentration CO2 reduction only under anaerobic conditions due to their sensitivity to oxygen. 3.3.2. CO2 Photoreduction Directly from Air. Direct aerobic CO2 photoconversion can be achieved by modifying local catalytic environments with specialized materials to increase the local CO2 concentration (for improved rate kinetics and mass transport) and to ward off oxygen, favoring CO2 reduction over O2 reduction. This was attempted recently by the Wang group, who employed a composite photocatalyst consisting of a hollow TiO2 core with surface-coated hyper- cross-linked porphyrin-based polymers coordinated to active Pd(II) sites (for CO2 reduction) to achieve direct aerobic CO2 photoconversion to CH4 under ultraviolet−visible (UV−vis) light irradiation (Figure 6d).135 Here, the TiO2 generated electron−hole pairs upon light irradiation and also catalyzed water oxidation as the counter reaction on its surface. The surface-deposited porphyrin-based polymer ensured high CO2 availability near the Pd(II) centers, by capturing CO2 from air, with the Pd atoms serving as active catalytic centers for CH4 formation. Employing this strategy, the authors reported a 12% conversion yield of CO2 to CH4 from air after 2 h of UV−vis irradiation (325−780 nm).135 Along similar lines, Zhang, Zhao, Sun, and co-workers have reported a series of hexagonal tungsten bronzematerials with the formula M0.33WO3 (M being alkali metals such as K, Rb, Cs) with exposed reactive {010} facets that are active in direct aerobic CO2 reduction under UV−vis-NIR illumination (Figure 6e).136 These materials were prepared solvothermally from tungsten hexacarbonyl (W(CO)6) and metal nitrate precursors, among which Rb0.33WO3 showed the most activity in aerobic CO2 photoreduction to methanol under full-spectrum radiation (350−2500 nm) or even selective near-infrared (NIR) irradiation (λ > 800 nm), producing methanol with 98% selectivity after 4 reaction hours and ∼4%CO2 conversion yield. Doping these structures with molybdenum (3−5%), specifically in Cs0.33WO3, can further enhance the catalytic activity several- Journal of the American Chemical Society pubs.acs.org/JACS Perspective https://doi.org/10.1021/jacs.5c21750 J. Am. Chem. Soc. 2026, 148, 10267−10285 10275 pubs.acs.org/JACS?ref=pdf https://doi.org/10.1021/jacs.5c21750?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as fold (3−4×) under anaerobic conditions.143 Other structures, such as rose-like assembled bismuth oxychloride (BiOCl) nanosheets rich in bismuth vacancies with exposed active {001} facets, are also found to be active for CO2 capture and photoconversion from air, with activities reaching around 20 μmol g−1 h−1 for CO production under a UV−vis irradiation for 5 h.135,144,145 A few notes on the challenges in aerobic CO2 photo- conversion and semiconductor photocatalysis in general are warranted here. First, the kinetic activities of these photo- catalytic systems remain low due to high charge recombination rates. Consequently, the analyzed product amounts are often small and subject to large errors.146,147 In CO2 photoreduction specifically, many products, such as CO and CH4, can also form from impurity photodegradation.141 Therefore, additional verification methods, including robust controls and isotope- labeling experiments, are necessary to identify CO2-derived products and calculate true catalytic rates.148 This issue is particularly prominent in direct photocatalysis of aerobic CO2, where low CO2 availability and high oxygen levels further promote the degradation of non-CO2 carbon sources such as organics.75 3.3.3. CO2 Photoreduction Following Direct Air Capture. Besides direct photochemical CO2 conversion from air, where the product is typically diluted in O2 and N2 (Figure 3), CO2 can alternatively be precaptured in solution, followed by photoreduction. Han, Liu, and co-workers have shown that CO2 from air can be precaptured using a task-specific ionic liquid consisting of a tetrabutylphosphonium cation and a pyridinium 2-oxide anion [P4444][P-2-O].144 Along with atmospheric CO2, the ionic liquid also captures atmospheric moisture to form a bicarbonate species. The captured CO2 (as bicarbonate) is directly reduced photocatalytically in the next step by using a pyrene-based conjugate polymer. ACO production rate of 47.37 μmol g−1 h−1 was obtained under visible light irradiation using triethanolamine as the sacrificial electron donor, with around 98% selectivity for CO formation due to suppression of the H2 evolution reaction in the ionic liquid medium. When employing a localized capture (by amines, hydroxides, zeolites) near catalytic centers, it is worth noting that CO2 in its captured state is thermodynamically more stable and kinetically more inert than free CO2. Thus, while in situ capture increases local CO2 concentrations (in the captured form), subsequent conversion is often challenging without prior CO2 release.112 Addressing this issue, we have designed a stepwise dual-bed direct air-to-fuel reactor that captures, concentrates, and converts CO2 from air into CO in a sequential manner using sunlight (Figure 6f).75 The photoreactor involves a transparent glass tube reactor with two separate fixed reaction beds�one for DAC and another for CO2 photoutilization�mounted on a parabolic trough reflector for sunlight concentration (3−5 kW m−2; 3−5 sun) (Figure 6f). The upstream DAC bed contains a solid silica- amine adsorbent to capture CO2 from air during nighttime ‘dark’ operation. During the day, solar light is concentrated onto the tube, heating the capture bed to temperatures exceeding 100 °C (a photothermal cover is used for efficient solar heating) and facilitating the release of air-captured CO2 in a concentrated stream toward the downstream utilization chamber. Depending on the flow rate, CO2 concentrations of more than a thousand times (of air) can be achieved (from 0.04% to >40% v/v). The downstream bed contains molecularly engineered titania nanoparticles with anchored phosphonated Co bis(terpyridine) CO2 reduction catalysts supported on alumina or silica nanopowder (Figure 6f, right) that use concentrated sunlight to convert incident CO2 to syngas. PET waste-derived ethylene glycol is presupplied to the conversion bed, which serves as the electron source (reductant), decreases overall energy demand, avoids explosive oxygen-fuel mixture formation, and is trans- formed into value-added products during the process (all of which may ultimately contribute to the practicality of this process). Although this nascent technology currently exhibits low solar-to-chemical efficiency, future improvements are anticipated, in terms of enhanced catalyst activity, stability, and solar absorption. 3.4. The Inorganic−Biological Hybrid Pathway One primary reason artificial conversion of CO2 from air has been challenging is its low ambient concentration, but nature has developed intricate biological mechanisms to address this challenge. Nature’s ability to fix aerobic CO2 can be exploited to design a hybrid approach where biological organisms are employed for low-concentration aerobic CO2 fixation (via reduction) and integrated with artificial chemical systems to provide the required energy (for example, via solar light Figure 7. Inorganic−biological hybrid solar air-to-fuel technologies. (a) The electrochemical biohybrid setup for aerobic CO2 reduction to C3−C5 alcohols under an electrochemical bias, with a shown biological CO2 fixation pathway152,153 (OER, HER, and PHA denote the oxygen evolution reaction, hydrogen evolution reaction, and polyhydroxyalkanoate, respectively). (b) The photovoltaic integration of the biohybrid electrolysis setup using an external triple junction solar cell.154 Journal of the American Chemical Society pubs.acs.org/JACS Perspective https://doi.org/10.1021/jacs.5c21750 J. Am. Chem. Soc. 2026, 148, 10267−10285 10276 https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig7&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig7&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig7&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig7&ref=pdf pubs.acs.org/JACS?ref=pdf https://doi.org/10.1021/jacs.5c21750?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as harvesting). Among biological organisms, Cupriavidus necator (formerly known as Ralstonia eutropha) is a soil bacterium with several intriguing capabilities. It can easily adapt between heterotrophic and autotrophic modes, meaning it can grow either by using other organic carbon sources (heterotrophic) or produce its own carbon-containing biomass from inorganic carbon, including atmospheric CO2 (autotrophic). In its autotrophic mode, C. necator can utilize H2 (through hydro- genase enzymes (H2ases)) as an energy source to fix ambient CO2 into biomass for its growth. Under nutrient-deficient conditions, the biomass formation pathway switches to a carbon-storing mechanism that synthesizes polyhydroxyalka- noate (PHA) at high concentrations instead of forming biomass.149,150 Perhaps most intriguingly, the PHA synthesis pathway following CO2 fixation under nutrition-deficient conditions can be genetically engineered in this bacterium to produce targeted energy-rich carbon products, including fusel alcohols (C3−C5).151 3.4.1. Bioelectrochemistry without Solar Integration. The genetically engineered C. necator bacterium’s ability to fix atmospheric CO2 into fusel alcohols using H2 under nutrient- deficient conditions can be combined with H2 production through solar water splitting to synthesize (C3−C5) bioalcohols from atmospheric CO2 using sunlight, as demonstrated by Nocera, Silver, and colleagues.152−156 Their biohybrid technol- ogy, called the Bionic Leaf, merges biological CO2 fixation with Nocera’s previously developed artificial leaf technology for solar H2 production,157,158 enabling solar-powered aerobic CO2 conversion into liquid fuels (Figure 7a). A similar approach was previously explored by Liao and colleagues using genetically engineered C. necator for electrobiofuel (isobutanol) produc- tion, utilizing formic acid as an energy vector.159 Initial reports on the Bionic Leaf focused on the electro- chemical aspects, investigating the potential integration of these chemical and biological pathways via intermediate H2 production.153 Major innovations involved developing efficient water electrolysis systems that can operate under conditions conducive to bacterial growth, including a moderate pH (6−8) and low cell potentials (2−3 V). A self-healing cobalt phosphate (CoPi) anode catalyst was found to be effective for catalyzing the oxygen evolution reaction at near-neutral pH, whereas a NiMoZn alloy was used as the cathode catalyst. The electrolyte consisted of CO2-saturated phosphate buffer (pH 6.5−7.5; minimal medium) with an added culture ofC. necator (wild-type or engineered). When this electrochemical cell was operated at a potential of nearly 2.7−3.0 V with wild-type C. necator, rapid bacterial biomass growth was observed by optical density analysis due to the consumption of the in situ generated H2 by the bacteria. At lower potentials (<2.7 V), a loss in bacterial growth and activity was observed due to the formation of H2O2 and other reactive oxygen species (ROS). When operated at 3.0 Vwith a genetically engineeredC. necator strain in the electrolyte specifically designed for targeted isopropanol synthesis, the selective formation of isopropanol via in situ CO2 fixation and reduction was observed (Figure 7a). Isopropanol concentrations in the electrolyte reached 216 mg L−1 after 5 days, with 90% carbon selectivity toward isopropanol (current densities around 5 mA cm−2, cell voltage 3.0 V). The required cell potential was later reduced to 2.2 V by using an alternative cathode comprising a cobalt phosphorus (Co−P) catalyst that minimized the formation of H2O2 and ROS at these low potentials.152 Furthermore, the Co−P cathode and CoPi anode can work synergistically to minimize leached cobalt in the electrolyte, enabling it to be transported to and deposited on the anode, leading to an increased cell viability. Using this approach, effective biological fixation of CO2 from air (containing 400 ppm of CO2) into biomass was demonstrated with wild-type C. necator at an overall electrochemical cell voltage of 2.0 V and at current densities of ∼5 mA cm−2, with an electricity-to-biomass efficiency of around 20%. Using genetically engineered C. necator strains, the product selectivity can be altered to produce C3 or C4 + C5 alcohols, with 25−40% energy efficiencies from pure CO2. 3.4.2. Bioelectrochemical with Solar Integration. Low required cell potentials (≤2 V) also enable efficient integration of the biological−inorganic hybrid electrolyzers with solar photovoltaic cells (Figure 7b).154 The required cell voltage was obtained from a triple-junction solar cell consisting of Ge, GeAs, and GeInP2, with bandgaps of 0.6, 1.42, and 1.9 eV, respectively. The solar cell produced an open-circuit voltage of 2.4 V, with peak power observed near 2.0 V at a current density of ∼10 mA cm−2. The attached hybrid electrolyzer contained Co−P and CoPi catalysts as the cathode and anode, respectively, with wild- type C. necator in the electrolyte medium for biological CO2 fixation using in situ generatedH2.When no external voltage was applied, the integrated photovoltaic-driven biohybrid electro- lyzer operated at a potential difference of approximately 2.3 V across the electrodes with a current density of 7 mA cm−2, producing bacterial biomass from pure CO2 with an energy (solar-to-chemical) efficiency of around 6.1%. The efficiency was lower than the achievable peak (∼10%, photovoltaic efficiency × electrolyzer efficiency) due to a voltage mismatch between the solar cell output and the electrolyzer input. While this study focused primarily on the utilization of pure CO2, activity for CO2 fixation from the aerobic atmosphere can be expected based on previous reports. In addition to CO2 fixation to biomass or carbon-based alcohols, the bacterium can be engineered to produce fine chemicals, including pharmaceut- icals, or even fertilizer (NH3) through N2 fixation (bionic leaf- N).160−163 4. DISCUSSION Several approaches are thus being explored for solar air-to-fuel synthesis to enable future utilization of atmospheric CO2. These technologies are at early stages, with technological readiness levels (TRLs) ranging from 2 to 5. Significant technological improvements, both in DAC and in solar-powered CO2 conversion, along with their effective integration, are needed to make solar air-to-fuel technologies a market reality. Key features of representative examples of these technological approaches are summarized in Table 1. Currently, the thermochemical pathway (Figure 4) is at tentative TRL values of 3−5. The core technology is being trialed by the spinout company Synhelion to produce solar aviation fuel at several thousand liters per year.164 However, the CO2 here is captured from concentrated biogenic emissions rather than air to improve economics. The cost of carbon capture increases significantly when transitioning to ultradilute sources such as air. Thus, any fuel produced via photothermal technology following DAC would be more expensive than current biogenic emission-derived fuels. Under optimistic scenarios, the price of synthetic aviation fuel from air-derived CO2 produced by this technology is estimated at around $2−$5 per liter, compared to virgin fossil-based aviation fuels at <$1 per liter.89 Another recent study has reported a tentative price of air- Journal of the American Chemical Society pubs.acs.org/JACS Perspective https://doi.org/10.1021/jacs.5c21750 J. Am. Chem. Soc. 2026, 148, 10267−10285 10277 pubs.acs.org/JACS?ref=pdf https://doi.org/10.1021/jacs.5c21750?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as derived methanol by this route at near $8 per liter, markedly higher than its current market price (<$1 per liter).165 The prices can be reduced by increasing the overall solar-to- fuel efficiency of the system from its current 1% to 10%, particularly by optimizing the syngas production process in the solar refinery. This can be addressed by improving heat recovery as radiative heat loss is significant at high operating temperatures (1000−1500 °C) and is being explored as part of the European SUN-to-LIQUID II project.166 Opportunities also lie in discovering alternative oxygen-transport materials that can facilitate the thermochemical cycle at lower temperatures,167,168 achievable in lower sunlight concentrations and, consequently, reducing radiative heat loss and area intensity (Figure 8). Efforts are ongoing in this regard, focusing on doping ceria with other oxide materials. The use of earth-abundant, noncritical minerals would aid large-scale adoption, and iron-based oxides show promise, but their high-temperature passivation remains a challenge.169,170 The mature process of solar thermal electricity generation using concentrated solar power with steam turbines171 could help scale up this relatively new fuel generation technology, utilizing existing solar fields. Still, the need for high temperatures, large-area solar fields, high capital expenditure for solar concentrators, large amounts of ceria (a critical mineral), and low specific product yield (mass of product per unit mass of ceria per cycle) could persist as problems for the foreseeable future in the absence of any significant breakthroughs. The photovoltaic-driven electrochemical pathway (Figure 5) does not suffer from significant radiative heat loss (operating at near-ambient temperatures) and is not limited by Carnot inefficiencies. However, the reported developments are still in the early stages. Direct photovoltaic-driven electrochemical reduction of aerobic CO2 in solution is more challenging as itT ab le 1. O ve rv ie w of R ep re se nt at iv e So la r A ir -t o- Fu el T ec hn ol og ie s T ec hn ol og ic al ap - pr oa ch C O 2 ca pt ur e m et ho d C on ve rs io n te ch no lo gy O pe ra tin g te m - pe ra tu re ra ng es C O 2 co n- ve rs io ns Pr od uc ts So la rt o fu el effi - ci en cy M aj or effi ci en cy lo ss m aj or ad va n- ta ge s m aj or co nc er ns te nt at iv e T RL a re f So la r− ph ot ot he r- m al So lid am in e- ba se d ad so rb - en ts T he rm oc he m ic al lo op in g 90 0− 15 00 °C 20 − 40 % H 2 (7 5− 90 % )b C O (6 − 10 % ) (f ur th er to m et ha no lo r ke ro se ne ) 1− 5% Ra di at iv e he at lo ss M at ur e so la r th er m al fa - ci lit ie s Ar ea in te ns ity ,h ea t lo ss ,C ap Ex f , cr iti ca l m at er ia ls 3− 5 89 Ph ot ov ol ta ic − el ec tr o- ch em ic al Aq ue ou s hy - dr ox id e or am in o ac id so lu tio ns D ire ct ca rb on at e an d ca rb am at e el ec tr ol ys is RT h − 80 °C 0− 10 % H 2 (5 0− 90 % ),c an d C O (1 0− 50 % ) or C 2H 4 (5 − 12 % ) or H C O 2� (2 0− 80 % ) 3− 8% e El ec tr o- ch em ic al ov er po te nt ia la nd re sis ta nc e PV g effi ci en cy H ig h ar ea la c- tiv ity (f or el ec tr ol ys is) H ig h ca pe x, ce ll st ab ili ty ,m em br an e pr ic es ,c ar bo n co n- ve rs io n 3− 4 10 8, 10 9, 11 4, 12 0 D ire ct ph ot o- ch em ic al So lid ad so rb - en ts /p ho to ca - ta ly st m at er ia l So la rc at al ys is us in g m ol ec ul es or se m ic on du ct or s RT − 10 0 °C 0− 10 % H 2 (2 0− 30 % )b an d C O (7 0− 80 % ), or C H 4 (> 90 % ), or M eO H (> 95 % ) 0. 05 − 1% C ha rg e ca rr ie rr ec om - bi na tio n Lo w su n- lig ht ab so rp tio n Lo w C ap Ex f H ig h sc al - ab ili ty Lo w ac tiv ity ,m at er ia l st ab ili ty 2− 3 75 ,1 35 ,1 36 In or ga ni c− bi ol og - ic al hy br id Bi ol og ic al C O 2 fix at io n by C . ne ca to r (P ho to )e le ct ro ly sis w ith m ic ro bi al C O 2 co nv er sio n RT − 40 °C 90 − 10 0% Li qu id fu el s (C 3 or C 4− C 5) (5 5− 70 % ), or bi om as s( 30 − 45 % ) 3− 6% d ,e Ph ot ov ol ta ic el ec tr o- ch em ic al in te gr at io n PV effi ci en cy Bi ol og ic al in - or ga ni c in - te gr at io n Sc al ab ili ty ,r ea ct io n ra te 3− 4 15 2 a T RL de no te s th e te ch no lo gy re ad in es s le ve l. b H 2 ge ne ra te d fro m co ad so rb ed m oi st ur e. c H 2 ge ne ra te d fro m aq ue ou s so lu tio n. d As su m in g a so la r ce ll effi ci en cy of 20 % ,c ou pl ed to th e el ec tr ol yz er . e T en ta tiv e effi ci en cy fo r C O 2 co nv er sio n fro m ai r, effi ci en cy hi gh er fo r pu re C O 2. f C ap Ex m ea ns C ap ita lE xp en di tu re .g PV de no te s ph ot ov ol ta ic .h RT de no te s ro om te m pe ra tu re . Figure 8. Future research directions among different technological routes. Journal of the American Chemical Society pubs.acs.org/JACS Perspective https://doi.org/10.1021/jacs.5c21750 J. Am. Chem. Soc. 2026, 148, 10267−10285 10278 https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig8&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig8&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig8&ref=pdf https://pubs.acs.org/doi/10.1021/jacs.5c21750?fig=fig8&ref=pdf pubs.acs.org/JACS?ref=pdf https://doi.org/10.1021/jacs.5c21750?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as combines the difficulty of low CO2 concentration with its low solubility in water. Consequently, the initial capture of CO2 in an electrolyte solution (using amines, hydroxides, etc), followed by photovoltaic-driven electrolysis, is likely a more manageable approach.172,173 The captured-CO2 electrochemical reduction systems can achieve high current densities (0.1−0.5 A cm−2 levels) and, consequently, high specific area activity. However, the low carbon conversion efficiencies and the high over- potentials required for both the oxygen evolution reaction and the air-captured CO2 reduction reaction need to be addressed.174 Regarding the latter, electrolyte engineering with different carbon capture solutions could establish a balance between capture and conversion, facilitating rapid direct air CO2 capture and its subsequent reduction at low potentials.112 Replacing water oxidation with a more energetically favorable waste-derived substrate oxidation can also decrease the overall cell voltage requirement for air-captured CO2 reduction (to ∼1 V) while providing a way to valorize waste materials (Figure 8).175 New earth-abundant metal-based electrocatalysts can be developed, moving away from noble metals (Au, Ag), which can retain activity in aerobic CO2-capturing electrolytes.176,177 The long-term stability of captured CO2 electrolyzers when operated at high current densities with high carbon conversion efficiencies remains to be explored. The use of bipolar membranes could be avoided when possible due to their high cost, relatively complex fabrication, and high transmembrane electrical resistance at high current densities.178,179 Additional operational complexities related to carbonate precipitation and CO2 crossover across the membrane must be addressed before the systems can be scaled up. Furthermore, consideration should be given to optimizing the integration of photovoltaic modules with electrolyzers (either as separate units or integrated buried- junction units) to match the photovoltaic module’s output voltage and current to the electrolyzer’s load, to maximize solar- to-chemical efficiencies (Figure 8). Additional complexities arising from low CO2 solubility in aqueous electrolyte solutions can be circumvented by moving to gas-phase systems.180−182 Direct photochemical air-to-fuel conversion (Figure 6), powered by sunlight, can be developed in a straightforward, scalable setup with low capital expenditure, a key advantage of direct photocatalysis.183,184 However, the activities of direct photochemical systems remain too low for their commercial applications. The primary reasons for this are attributed to rapid charge-carrier recombination, incomplete light absorption, and degradation of photocatalyst activity over time.185,186 Recombi- nation can be minimized by developing materials containing heterojunctions to ensure facile charge separation upon their photoinduced generation.187−189 Similarly, improved light absorption by developing visible-light-responsive photocatalysts needs to be pursued to utilize a broad solar spectrum.190,191 During direct photocatalytic aerobic CO2 reduction, care must be taken to separate fuels from air after photoconversion to avoid the dangers posed by air−fuel mixtures. Additional difficulty arises from the challenge of competing aerobic O2 reduction. The dual-step approach introduced by us provides a workaround by concentrating CO2 and removing O2 in an upstream gas-phase process.75 Still, the efficiencies in both solar CO2 concentration and CO2 conversion require improvement. The field will benefit from breakthroughs in photocatalyst development,192 leading to enhanced light absorption, charge separation, electron transfer, and stability, ultimately bringing it closer to the desirable 5% solar-to-chemical efficiency target (Figure 8).131,193,194 The Bionic Leaf technology employs a hybrid approach by utilizing natural systems to facilitate CO2 fixation, which is often the most challenging aspect for aerobic CO2 conversion, while generating the necessary energy through solar H2 production (Figure 7). The bacteria can be genetically engineered to produce a variety of fuels and chemicals, providing access to products that are not readily accessible from purely synthetic devices.195,196 Further work can thus engineer bacterial strains for the synthesis of fine chemicals. The use of living organisms, however, requires that contaminants and the medium temper- ature be controlled during operation to prevent cell death. Among future explorations, the scalability of this technology for carbonaceous fuel production can be investigated. The current major efficiency loss stems from the efficiency cap of the solar cell. The voltage and current matching between the photovoltaic output and the biohybrid electrolyzer input needs to be tuned to ensure the entire process operates at the maximum possible solar conversion efficiency.154 As it currently uses a bacterial batch process for CO2 conversion, the reaction rates should be optimized to achieve the highest possible CO2 conversion from aerobic CO2 in the shortest possible time. Overall, this technological approach holds promise but requires further development beyond its current stage, particularly in terms of scalability and economic viability (Figure 8). 5. OUTLOOK Despite several advances, solar air-to-fuel technologies require substantial further development. The thermochemical route, though the most mature and capable of producing tangible air- to-fuel products, remains capital-intensive and operates at extremely high temperatures that challenge material and system stability. Moving toward lower reaction temperatures using alternative oxygen-transport materials will be crucial. Mean- while, electrochemical systems, particularly direct carbonate, bicarbonate, and carbamate electrolyzers, show promise but require further research to improve carbon conversion efficiency, prevent crossover and precipitation, enhance stability, optimize energy use, and improve operational flexibility. Technoeconomic analyses under relevant industrial conditions are necessary, with a recent study identifying iridium costs from anodic water oxidation as a significant cost contributor in direct carbonate electrolysis for ethylene production.197 Compared to the electrocatalytic air-to-fuel systems, current photocatalytic systems are at a lower TRL (2−3) due to their lower activity. Fundamental research in photocatalyst development for both gaseous and chemically captured CO2 photoreduction is required to enhance catalytic efficiencies. Likewise, the biohybrid approach requires further study, particularly regarding system stability, long-term energy efficiency, and technoeco- nomic factors, before large-scale implementation can be considered. The world consumes around 15 billion liters of crude oil per day, and substituting this vast amount with sustainable synthetic fuels from air is a massive challenge. Electrification and the hydrogen economy canmake significant strides in decarbonizing some industrial sectors, including light transport, but synthetic fuels will be needed to meet the liquid fuel demands of the aviation, heavy transport, and chemical industries to produce plastics as well as bulk and fine chemicals with low carbon or net- zero emissions. The scientific community’s interest in tackling this formidable challenge and making solar air-to-fuel a reality Journal of the American Chemical Society pubs.acs.org/JACS Perspective https://doi.org/10.1021/jacs.5c21750 J. Am. Chem. Soc. 2026, 148, 10267−10285 10279 pubs.acs.org/JACS?ref=pdf https://doi.org/10.1021/jacs.5c21750?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as has been evident over the past decade, with new partnerships, consortia, and research centers emerging rapidly.198 However, major hurdles in the industrial and political spheres need to be overcome to realize this ambition and to implement commercial clean technologies. Support from government policies for the use of green synthetic fuels, even as a small fraction blended with current fuels, will be necessary for the early adoption of these emerging technologies and place them on the learning curve.199 Harvesting and utilizing atmospheric CO2 to store solar energy as fuels would enable us to effectively regulate atmospheric CO2 levels and meet the energy demands of our civilization while enabling the adoption of a circular carbon economy.200 How effectively we can achieve this and how long it will take will have a decisive impact on our society’s future. ■ AUTHOR INFORMATION Corresponding Authors Sayan Kar − Department of Sustainable Energy Engineering, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India; Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.; orcid.org/0000-0002-6986-5796; Email: sayank@ iitk.ac.in Erwin Reisner − Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.; orcid.org/0000-0002-7781-1616; Email: reisner@ ch.cam.ac.uk Complete contact information is available at: https://pubs.acs.org/10.1021/jacs.5c21750 Notes The authors declare the following competing financial interest(s): A patent application covering integrated direct air capture and utilization into solar fuels has been filed by the University of Cambridge technology transfer office, Cambridge Enterprise with S.K. and E.R. as co-inventors (application no GB2408950.0). ■ ACKNOWLEDGMENTS This work is supported in part by the Indian Institute of Technology Kanpur (through the Research Initiation Grant IITK/SEE/2025057 to S.K.), the Chandrakanta Kesavan Centre for Climate Policy and Energy Solutions, IIT Kanpur (through research grant DORA/DORA/2021136K to S.K.), UK Research & Innovation (UKRI for ERC Advanced Grant, EP/X030563/1 to E.R.), and the UK Department of Science, Innovation & Technology and the Royal Academy of Engineer- ing Chair in Emerging Technologies programme (CIET-2324- 83 to E.R.). ■ REFERENCES (1) Berner, R. A. The long-term carbon cycle, fossil fuels and atmospheric composition. Nature 2003, 426, 323−326. (2) Ahn, J.; Brook, E. J. Atmospheric CO2 and Climate on Millennial Time Scales During the Last Glacial Period. Science 2008, 322, 83−85. (3) Zeebe, R. E.; Ridgwell, A.; Zachos, J. C. Anthropogenic carbon release rate unprecedented during the past 66 million years.Nat. Geosci. 2016, 9, 325−329. (4) Foote, E. Circumstances affecting the heat of the sun’s rays. Am. J. Sci. Arts 1856, 22, 382−383. (5) Tyndall, J. I. The Bakerian Lecture. On the absorption and radiation of heat by gases and vapours, and on the physical connexion of radiation, absorption, and conduction. Philos. Trans. R. Soc. 1861, 151, 1−36. (6) Arrhenius, S., XXXI. On the influence of carbonic acid in the air upon the temperature of the ground. Philos. Mag. S. 1896, 41, 237−276. (7) Magnan, A. K.; Pörtner, H.-O.; Duvat, V. K. E.; Garschagen, M.; Guinder, V. A.; Zommers, Z.; Hoegh-Guldberg, O.; Gattuso, J.-P. Estimating the global risk of anthropogenic climate change. Nat. Clim. Change 2021, 11, 879−885. (8) Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report, Working Group III: Mitigation of Climate Change (2022). (9) Gabrielli, P.; Gazzani, M.; Mazzotti, M. The Role of Carbon Capture and Utilization, Carbon Capture and Storage, and Biomass to Enable a Net-Zero-CO2 Emissions Chemical Industry. Ind. Eng. Chem. Res. 2020, 59, 7033−7045. (10) LeClerc, H. O.; Erythropel, H. C.; Backhaus, A.; Lee, D. S.; Judd, D. R.; Paulsen, M. M.; Ishii, M.; Long, A.; Ratjen, L.; Gonsalves Bertho, G.; et al. The CO2 Tree: The Potential for Carbon Dioxide Utilization Pathways. ACS Sustain. Chem. Eng. 2025, 13, 5−29. (11) Goeppert, A.; Czaun, M.; Surya Prakash, G. K.; Olah, G. A. Air as the renewable carbon source of the future: an overview of CO2 capture from the atmosphere. Energy Environ. Sci. 2012, 5, 7833−7853. (12) Kurt, E.; Qin, J.; Williams, A.; Zhao, Y.; Xie, D. Perspectives for Using CO2 as a Feedstock for Biomanufacturing of Fuels and Chemicals. Bioengineering 2023, 10, 1357. (13) Marchese, M.; Buffo, G.; Santarelli, M.; Lanzini, A. CO2 from direct air capture as carbon feedstock for Fischer−Tropsch chemicals and fuels: Energy and economic analysis. J. CO2 Util. 2021, 46, 101487. (14) Wang, Y.; Guo, J.; Qu, L.; Webley, P.; Ding, H.; Li, G. K. Syngas production from the air. Chem Catal. 2025, 5, 101254. (15) Liu, Y.; Lu, X.-B. Current Challenges and Perspectives in CO2- Based Polymers. Macromolecules 2023, 56, 1759−1777. (16) Vidal, F.; van der Marel, E. R.; Kerr, R. W. F.; McElroy, C.; Schroeder, N.; Mitchell, C.; Rosetto, G.; Chen, T. T. D.; Bailey, R. M.; Hepburn, C.; et al. Designing a circular carbon and plastics economy for a sustainable future. Nature 2024, 626, 45−57. (17) Chatterjee, S.; Huang, K.-W. Unrealistic energy and materials requirement for direct air capture in deep mitigation pathways. Nat. Commun. 2020, 11, 3287. (18) Realmonte, G.; Drouet, L.; Gambhir, A.; Glynn, J.; Hawkes, A.; Köberle, A. C.; Tavoni, M. An inter-model assessment of the role of direct air capture in deep mitigation pathways.Nat. Commun. 2019, 10, 3277. (19) Terlouw, T.; Pokras, D.; Becattini, V.; Mazzotti, M. Assessment of Potential and Techno-Economic Performance of Solid Sorbent Direct Air Capture with CO2 Storage in Europe. Environ. Sci. Technol. 2024, 58, 10567−10581. (20) Kazlou, T.; Cherp, A.; Jewell, J. Feasible deployment of carbon capture and storage and the requirements of climate targets. Nat. Clim. Change 2024, 14, 1047−1055. (21) Victoria, M.; Haegel, N.; Peters, I. M.; Sinton, R.; Jäger-Waldau, A.; del Cañizo, C.; Breyer, C.; Stocks, M.; Blakers, A.; Kaizuka, I.; et al. Solar photovoltaics is ready to power a sustainable future. Joule 2021, 5, 1041−1056. (22) Hayat, M. B.; Ali, D.; Monyake, K. C.; Alagha, L.; Ahmed, N. Solar energy � A look into power generation, challenges, and a solar- powered future. Int. J. Energy Res. 2019, 43, 1049−1067. (23) Kärkäs, M. D.; Verho, O.; Johnston, E. V.; Åkermark, B. Artificial Photosynthesis: Molecular Systems for Catalytic Water Oxidation. Chem. Rev. 2014, 114, 11863−12001. (24) Zhang, B.; Sun, L. Artificial photosynthesis: opportunities and challenges of molecular catalysts.Chem. Soc. Rev. 2019, 48, 2216−2264. (25)Whang, D. R.; Apaydin, D. H. Artificial Photosynthesis: Learning from Nature. ChemPhotoChem 2018, 2, 148−160. (26) Glaser, P. E. Power from the Sun: Its Future. Science 1968, 162, 857−861. (27) Mori, S.; Hashimoto, R.; Hisatomi, T.; Domen, K.; Saito, S. Artificial photosynthesis directed toward organic synthesis. Nat. Commun. 2025, 16, 1797. Journal of the American Chemical Society pubs.acs.org/JACS Perspective https://doi.org/10.1021/jacs.5c21750 J. Am. Chem. Soc. 2026, 148, 10267−10285 10280 https://pubs.acs.org/action/doSearch?field1=Contrib&text1="Sayan+Kar"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdf https://orcid.org/0000-0002-6986-5796 https://orcid.org/0000-0002-6986-5796 mailto:sayank@iitk.ac.in mailto:sayank@iitk.ac.in https://pubs.acs.org/action/doSearch?field1=Contrib&text1="Erwin+Reisner"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdf https://orcid.org/0000-0002-7781-1616 https://orcid.org/0000-0002-7781-1616 mailto:reisner@ch.cam.ac.uk mailto:reisner@ch.cam.ac.uk https://pubs.acs.org/doi/10.1021/jacs.5c21750?ref=pdf https://doi.org/10.1038/nature02131 https://doi.org/10.1038/nature02131 https://doi.org/10.1126/science.1160832 https://doi.org/10.1126/science.1160832 https://doi.org/10.1038/ngeo2681 https://doi.org/10.1038/ngeo2681 https://doi.org/10.1098/rstl.1861.0001 https://doi.org/10.1098/rstl.1861.0001 https://doi.org/10.1098/rstl.1861.0001 https://doi.org/10.1080/14786449608620846 https://doi.org/10.1080/14786449608620846 https://doi.org/10.1038/s41558-021-01156-w https://doi.org/10.1021/acs.iecr.9b06579?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.iecr.9b06579?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.iecr.9b06579?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acssuschemeng.4c07582?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acssuschemeng.4c07582?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1039/c2ee21586a https://doi.org/10.1039/c2ee21586a https://doi.org/10.1039/c2ee21586a https://doi.org/10.3390/bioengineering10121357 https://doi.org/10.3390/bioengineering10121357 https://doi.org/10.3390/bioengineering10121357 https://doi.org/10.1016/j.jcou.2021.101487 https://doi.org/10.1016/j.jcou.2021.101487 https://doi.org/10.1016/j.jcou.2021.101487 https://doi.org/10.1016/j.checat.2024.101254 https://doi.org/10.1016/j.checat.2024.101254 https://doi.org/10.1021/acs.macromol.2c02483?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.macromol.2c02483?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1038/s41586-023-06939-z https://doi.org/10.1038/s41586-023-06939-z https://doi.org/10.1038/s41467-020-17203-7 https://doi.org/10.1038/s41467-020-17203-7 https://doi.org/10.1038/s41467-019-10842-5 https://doi.org/10.1038/s41467-019-10842-5 https://doi.org/10.1021/acs.est.3c10041?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.est.3c10041?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.est.3c10041?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1038/s41558-024-02104-0 https://doi.org/10.1038/s41558-024-02104-0 https://doi.org/10.1016/j.joule.2021.03.005 https://doi.org/10.1002/er.4252 https://doi.org/10.1002/er.4252 https://doi.org/10.1021/cr400572f?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/cr400572f?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1039/C8CS00897C https://doi.org/10.1039/C8CS00897C https://doi.org/10.1002/cptc.201700163 https://doi.org/10.1002/cptc.201700163 https://doi.org/10.1126/science.162.3856.857 https://doi.org/10.1038/s41467-025-56374-z pubs.acs.org/JACS?ref=pdf https://doi.org/10.1021/jacs.5c21750?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as (28) Whittingham, C. P. The chemical mechanism of photosynthesis. Bot. Rev. 1952, 18, 245−290. (29) Direct Air Capture, IEA (2024) https://www.iea.org/energy- system/carbon-capture-utilisation-and-storage/direct-air-capture, ac- cessed Feb 24, 2026. (30) Sanz-Pérez, E. S.; Murdock, C. R.; Didas, S. A.; Jones, C. W. Direct Capture of CO2 from Ambient Air. Chem. Rev. 2016, 116, 11840−11876. (31) Custelcean, R. Direct Air Capture of CO2 Using Solvents. Annu. Rev. Chem. Biomol. Eng. 2022, 13, 217−234. (32) Bouaboula, H.; Chaouki, J.; Belmabkhout, Y.; Zaabout, A. Comparative review of direct air capture technologies: From technical, commercial, economic, and environmental aspects. Chem. Eng. J. 2024, 484, 149411. (33) Chen, Y.; Wu, R.; Hsu, P.-C. Perspective on distributed direct air capture: what, why, and how? npj Mater. Sustain. 2025, 3, 12. (34) IEA, Direct Air Capture 2022, IEA: Paris, (2022) https://www. iea.org/reports/direct-air-capture-2022, Licence: CC BY 4.0, accessed Feb 24, 2026. (35) Simari, C. Nanomaterials for Direct Air Capture of CO2: Current State of the Art, Challenges and Future Perspectives. Molecules 2025, 30, 3048. (36) Zhu, P.; Wu, Z.-Y.; Elgazzar, A.; Dong, C.;Wi, T.-U.; Chen, F.-Y.; Xia, Y.; Feng, Y.; Shakouri, M.; Kim, J. Y.; et al. Continuous carbon capture in an electrochemical solid-electrolyte reactor. Nature 2023, 618, 959−966. (37) Sharifian, R.; Wagterveld, R. M.; Digdaya, I. A.; Xiang, C.; Vermaas, D. A. Electrochemical carbon dioxide capture to close the carbon cycle. Energy Environ. Sci. 2021, 14, 781−814. (38) Li, H.; Zick, M. E.; Trisukhon, T.; Signorile, M.; Liu, X.; Eastmond, H.; Sharma, S.; Spreng, T. L.; Taylor, J.; Gittins, J. W.; et al. Capturing carbon dioxide from air with charged-sorbents.Nature 2024, 630, 654−659. (39) Stern, M. C.; Simeon, F.; Herzog, H.; Hatton, T. A. Post- combustion carbon dioxide capture using electrochemically mediated amine regeneration. Energy Environ. Sci. 2013, 6, 2505−2517. (40) Rahimi, M.; Diederichsen, K. M.; Ozbek, N.; Wang, M.; Choi, W.; Hatton, T. A. An Electrochemically Mediated Amine Regeneration Process with a Mixed Absorbent for Postcombustion CO2 Capture. Environ. Sci. Technol. 2020, 54, 8999−9007. (41) Hassan, A.; Afshari, M.; Rahimi, M. A Membraneless Electrochemically Mediated Amine Regeneration for Carbon Capture. Nat. Commun. 2025, 16, 6333. (42) Wang, M.; Herzog, H. J.; Hatton, T. A. CO2 Capture Using Electrochemically Mediated Amine Regeneration. Ind. Eng. Chem. Res. 2020, 59, 7087−7096. (43) Wang, T.; Lackner, K. S.; Wright, A. B. Moisture-swing sorption for carbon dioxide capture from ambient air: a thermodynamic analysis. Phys. Chem. Chem. Phys. 2013, 15, 504−514. (44) Wang, Y.; Kim, J.; Marreiros, J.; Rangnekar, N.; Yuan, Y.; Johnson, J. R.; McCool, B. A.; Realff, M. J.; Lively, R. P. Investigation of Moisture Swing Adsorbents for Direct Air Capture by Dynamic Breakthrough Studies. ACS Sustain. Chem. Eng. 2025, 13, 6554−6564. (45) Nicotera, I.; Enotiadis, A.; Simari, C. Quaternized Graphene for High-Performance Moisture Swing Direct Air Capture of CO2. Small 2024, 20, 2401303. (46) Seo, H.; Schretter, J.; Massen-Hane, M.; Hatton, T. A. Visible Light-Driven CO2 Capture and Release Using Photoactive Pyranine in Water in Continuous Flow. J. Am. Chem. Soc. 2024, 146, 26777−26785. (47) Baker, B. A.; Han, G. G. D. Light-driven direct air capture of CO2. Nat. Chem. 2025, 17, 1630−1631. (48) Purdy, M.; Wang, A. Y.; Drummer, M. C.; Nocera, D. G.; Liu, R. Y. Reversible fluorenol photobases that perform CO2 capture and concentration from ambient air. Nat. Chem. 2025, 17, 1680−1687. (49) Premadasa, U. I.; Bocharova, V.; Miles, A. R.; Stamberga, D.; Belony, S.; Bryantsev, V. S.; Elgattar, A.; Liao, Y.; Damron, J. T.; Kidder, M. K.; et al. Photochemically-Driven CO2 Release Using a Metastable- State Photoacid for Energy Efficient Direct Air Capture. Angew. Chem., Int. Ed. 2023, 62, No. e202304957. (50) Fujikawa, S.; Selyanchyn, R.; Kunitake, T. A new strategy for membrane-based direct air capture. Polym. J. 2021, 53, 111−119. (51) Castro-Muñoz, R.; Zamidi Ahmad, M.; Malankowska, M.; Coronas, J. A new relevant membrane application: CO2 direct air capture (DAC). Chem. Eng. J. 2022, 446, 137047. (52) Zito, A. M.; Clarke, L. E.; Barlow, J. M.; Bím, D.; Zhang, Z.; Ripley, K. M.; Li, C. J.; Kummeth, A.; Leonard, M. E.; Alexandrova, A. N.; et al. Electrochemical Carbon Dioxide Capture and Concentration. Chem. Rev. 2023, 123, 8069−8098. (53) Ahmad, B. I. Z.; Milner, P. J. Chemisorptive carbon capture sees the light. Trends Chem. 2025, 7, 529−540. (54) Xie, R. Y.; Chen, S.; Yong, J. Y.; Zhang, X. J.; Jiang, L. Moisture swing adsorption for direct air capture: Establishment of thermody- namic cycle. Chem. Eng. Sci. 2024, 287, 119809. (55) Long, D.; Li, J.; Qian, G.; Tang, L.; Ma, S.; Li, W.; Yu, X. Photocatalytic Reduction of Low-Concentration CO2: Progress and Challenges. Coord. Chem. Rev. 2026, 549, 217246. (56) rubisco form ii cbbM (3DPX-009987). Version 2, NIH 3D, 2025. https://3d.nih.gov/entries/3DPX-009987, accessed Feb 24, 2026. (57) Wakerley, D. W.; Reisner, E. Oxygen-tolerant proton reduction catalysis: much O2 about nothing? Energy Environ. Sci. 2015, 8, 2283− 2295. (58) Erb, T. J.; Zarzycki, J. A short history of RubisCO: the rise and fall (?) of Nature’s predominant CO2 fixing enzyme. Curr. Opin. Biotechnol. 2018, 49, 100−107. (59) Busch, F. A.; Sage, R. F. The sensitivity of photosynthesis to O2 and CO2 concentration identifies strong Rubisco control above the thermal optimum. New Phytol. 2017, 213, 1036−1051. (60) Prywes, N.; Phillips, N. R.; Tuck, O. T.; Valentin-Alvarado, L. E.; Savage, D. F. Rubisco Function, Evolution, and Engineering. Annu. Rev. Biochem. 2023, 92, 385−410. (61) Zhao, L.; Cai, Z.; Li, Y.; Zhang, Y. Engineering Rubisco to enhance CO2 utilization. Synth. Syst. Biotechnol. 2024, 9, 55−68. (62) Tcherkez, G. How atmospheric oxygen is captured by RuBisCO. Nat. Rev. Mol. Cell Biol. 2021, 22, 304. (63) Blankenship, R. E.; Tiede, D. M.; Barber, J.; Brudvig, G. W.; Fleming, G.; Ghirardi, M.; Gunner, M. R.; Junge, W.; Kramer, D. M.; Melis, A.; et al. Comparing Photosynthetic and Photovoltaic Efficiencies and Recognizing the Potential for Improvement. Science 2011, 332, 805−809. (64) Leegood, R. C. C4 photosynthesis: principles of CO2 concentration and prospects for its introduction into C3 plants. J. Exp. Bot. 2002, 53, 581−590. (65) Sage, R. F. The evolution of C4 photosynthesis. New Phytol. 2004, 161, 341−370. (66) Dodd, A. N.; Borland, A. M.; Haslam, R. P.; Griffiths, H.; Maxwell, K. Crassulacean acid metabolism: plastic, fantastic. J. Exp. Bot. 2002, 53, 569−580. (67) Edwards, E. J. Evolutionary trajectories, accessibility and other metaphors: the case of C4 and CAM photosynthesis.New Phytol. 2019, 223, 1742−1755. (68) Badger, M. R.; Price, G. D. CO2 concentrating mechanisms in cyanobacteria: molecular components, their diversity and evolution. J. Exp. Bot. 2003, 54, 609−622. (69) Turmo, A.; Gonzalez-Esquer, C. R.; Kerfeld, C. A. Carbox- ysomes: metabolic modules for CO2 fixation. FEMS Microbiol. Lett. 2017, 364, 176. (70) Zhu, H.-J.; Si, D.-H.; Guo, H.; Chen, Z.; Cao, R.; Huang, Y.-B. Oxygen-tolerant CO2 electroreduction over covalent organic frame- works via photoswitching control oxygen passivation strategy. Nat. Commun. 2024, 15, 1479. (71) Lakadamyali, F.; Kato, M.; Muresan, N. M.; Reisner, E. Selective Reduction of Aqueous Protons to Hydrogen with a Synthetic Cobaloxime Catalyst in the Presence of Atmospheric Oxygen. Angew. Chem., Int. Ed. 2012, 51 (37), 9381−9384. (72) Wang, M.; Ozden, A.; Tian, W.; Chen, J.; Chen, W.; Wang, L.; Wong, A. B.; Lum, Y. From Pollution to Value: Electrochemical Systems for Transforming Flue Gas into Chemicals and Fuels. Adv. Mater. 2025, 37, No. e09581. Journal of the American Chemical Society pubs.acs.org/JACS Perspective https://doi.org/10.1021/jacs.5c21750 J. Am. Chem. Soc. 2026, 148, 10267−10285 10281 https://doi.org/10.1007/BF02861739 https://www.iea.org/energy-system/carbon-capture-utilisation-and-storage/direct-air-capture https://www.iea.org/energy-system/carbon-capture-utilisation-and-storage/direct-air-capture https://doi.org/10.1021/acs.chemrev.6b00173?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1146/annurev-chembioeng-092120-023936 https://doi.org/10.1016/j.cej.2024.149411 https://doi.org/10.1016/j.cej.2024.149411 https://doi.org/10.1038/s44296-025-00056-w https://doi.org/10.1038/s44296-025-00056-w https://www.iea.org/reports/direct-air-capture-2022 https://www.iea.org/reports/direct-air-capture-2022 https://doi.org/10.3390/molecules30143048 https://doi.org/10.3390/molecules30143048 https://doi.org/10.1038/s41586-023-06060-1 https://doi.org/10.1038/s41586-023-06060-1 https://doi.org/10.1039/D0EE03382K https://doi.org/10.1039/D0EE03382K https://doi.org/10.1038/s41586-024-07449-2 https://doi.org/10.1039/c3ee41165f https://doi.org/10.1039/c3ee41165f https://doi.org/10.1039/c3ee41165f https://doi.org/10.1021/acs.est.0c02595?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.est.0c02595?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1038/s41467-025-61525-3 https://doi.org/10.1038/s41467-025-61525-3 https://doi.org/10.1021/acs.iecr.9b05307?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.iecr.9b05307?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1039/C2CP43124F https://doi.org/10.1039/C2CP43124F https://doi.org/10.1021/acssuschemeng.5c00227?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acssuschemeng.5c00227?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acssuschemeng.5c00227?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1002/smll.202401303 https://doi.org/10.1002/smll.202401303 https://doi.org/10.1021/jacs.4c07278?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/jacs.4c07278?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/jacs.4c07278?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1038/s41557-025-01972-z https://doi.org/10.1038/s41557-025-01901-0 https://doi.org/10.1038/s41557-025-01901-0 https://doi.org/10.1002/anie.202304957 https://doi.org/10.1002/anie.202304957 https://doi.org/10.1038/s41428-020-00429-z https://doi.org/10.1038/s41428-020-00429-z https://doi.org/10.1016/j.cej.2022.137047 https://doi.org/10.1016/j.cej.2022.137047 https://doi.org/10.1021/acs.chemrev.2c00681?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1016/j.trechm.2025.07.002 https://doi.org/10.1016/j.trechm.2025.07.002 https://doi.org/10.1016/j.ces.2024.119809 https://doi.org/10.1016/j.ces.2024.119809 https://doi.org/10.1016/j.ces.2024.119809 https://doi.org/10.1016/j.ccr.2025.217246 https://doi.org/10.1016/j.ccr.2025.217246 https://3d.nih.gov/entries/3DPX-009987 https://doi.org/10.1039/C5EE01167A https://doi.org/10.1039/C5EE01167A https://doi.org/10.1016/j.copbio.2017.07.017 https://doi.org/10.1016/j.copbio.2017.07.017 https://doi.org/10.1111/nph.14258 https://doi.org/10.1111/nph.14258 https://doi.org/10.1111/nph.14258 https://doi.org/10.1146/annurev-biochem-040320-101244 https://doi.org/10.1016/j.synbio.2023.12.006 https://doi.org/10.1016/j.synbio.2023.12.006 https://doi.org/10.1038/s41580-021-00344-y https://doi.org/10.1126/science.1200165 https://doi.org/10.1126/science.1200165 https://doi.org/10.1093/jexbot/53.369.581 https://doi.org/10.1093/jexbot/53.369.581 https://doi.org/10.1111/j.1469-8137.2004.00974.x https://doi.org/10.1093/jexbot/53.369.569 https://doi.org/10.1111/nph.15851 https://doi.org/10.1111/nph.15851 https://doi.org/10.1093/jxb/erg076 https://doi.org/10.1093/jxb/erg076 https://doi.org/10.1093/femsle/fnx176 https://doi.org/10.1093/femsle/fnx176 https://doi.org/10.1038/s41467-024-45959-9 https://doi.org/10.1038/s41467-024-45959-9 https://doi.org/10.1002/anie.201204180 https://doi.org/10.1002/anie.201204180 https://doi.org/10.1002/anie.201204180 https://doi.org/10.1002/adma.202509581 https://doi.org/10.1002/adma.202509581 pubs.acs.org/JACS?ref=pdf https://doi.org/10.1021/jacs.5c21750?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as (73) Kar, S.; Rahaman, M.; Andrei, V.; Bhattacharjee, S.; Roy, S.; Reisner, E. Integrated capture and solar-driven utilization of CO2 from flue gas and air. Joule 2023, 7, 1496−1514. (74) Li, Y. C.; Lee, G.; Yuan, T.; Wang, Y.; Nam, D.-H.; Wang, Z.; García de Arquer, F. P.; Lum, Y.; Dinh, C.-T.; Voznyy, O.; Sargent, E. H. CO2 Electroreduction from Carbonate Electrolyte. ACS Energy Lett. 2019, 4, 1427−1431. (75) Kar, S.; Kim, D.; BinMohamadAnnuar, A.; Sarma, B. B.; Stanton, M.; Lam, E.; Bhattacharjee, S.; Karak, S.; Greer, H. F.; Reisner, E. Direct air capture of CO2 for solar fuel production in flow. Nat. Energy 2025, 10, 448−459. (76) Kumar, A.; Madden, D. G.; Lusi, M.; Chen, K.-J.; Daniels, E. A.; Curtin, T.; Perry IV, J. J.; Zaworotko, M. J. Direct Air Capture of CO2 by Physisorbent Materials. Angew. Chem., Int. Ed. 2015, 54, 14372− 14377. (77) Wang, Y.; Li, G. K. The impact of co-adsorbed water on energy consumption and CO2 productivity in direct air capture systems. Sep. Purif. Technol. 2025, 354, 129415. (78) Zhang, H.; Goeppert, A.; Olah, G. A.; Prakash, G. K. S. Remarkable effect of moisture on the CO2 adsorption of nano-silica supported linear and branched polyethylenimine. J. CO2 Util. 2017, 19, 91−99. (79) Rim, G.; Song, M.; Proaño, L.; Ghaffari Nik, O.; Parker, S.; Lively, R. P.; Jones, C. W. Humidity Effects on Sub-Ambient Direct Air Capture of CO2 with Amine Functionalized Mg-Al LDHs and MMOs. ACS ES&T Eng. 2025, 5, 204−214. (80) Shang, B.; Zhao, F.; Choi, C.; Jia, X.; Pauly, M.; Wu, Y.; Tao, Z.; Zhong, Y.; Harmon, N.; Maggard, P. A.; et al. Monolayer Molecular Functionalization Enabled by Acid-Base Interaction for High-Perform- ance Photochemical CO2 Reduction. ACS Energy Lett. 2022, 7, 2265− 2272. (81) Chueh, W. C.; Haile, S. M. A thermochemical study of ceria: exploiting an old material for newmodes of energy conversion and CO2 mitigation. Philos. Trans. R. Soc., A 2010, 368, 3269−3294. (82) Scheffe, J. R.; Steinfeld, A. Thermodynamic Analysis of Cerium- Based Oxides for Solar Thermochemical Fuel Production. Energy Fuels 2012, 26, 1928−1936. (83) Abanades, S. A Review of Oxygen Carrier Materials and Related Thermochemical Redox Processes for Concentrating Solar Thermal Applications. Materials 2023, 16, 3582. (84) Steinfeld, A. Solar hydrogen production via a two-step water- splitting thermochemical cycle based on Zn/ZnO redox reactions. Int. J. Hydrogen Energy 2002, 27, 611−619. (85) Lichty, P.; Liang, X.; Muhich, C.; Evanko, B.; Bingham, C.; Weimer, A. W. Atomic layer deposited thin film metal oxides for fuel production in a solar cavity reactor. Int. J. Hydrogen Energy 2012, 37, 16888−16894. (86) Takacs, M.; Hoes, M.; Caduff, M.; Cooper, T.; Scheffe, J. R.; Steinfeld, A. Oxygen nonstoichiometry, defect equilibria, and thermodynamic characterization of LaMnO3 perovskites with Ca/Sr A-site and Al B-site doping. Acta Mater. 2016, 103, 700−710. (87) Jiang, Q.; Tong, J.; Zhou, G.; Jiang, Z.; Li, Z.; Li, C. Thermochemical COt splitting reaction with supported LaxA1‑xFeyB1‑yO3 (A = Sr, Ce, B = Co, Mn; 0⩽x, y⩽1) perovskite oxides. Sol. Energy 2014, 103, 425−437. (88) Boretti, A. Technology Readiness Level of Solar Thermochem- ical Splitting Cycles. ACS Energy Lett. 2021, 6, 1170−1174. (89) Schäppi, R.; Rutz, D.; Dähler, F.; Muroyama, A.; Haueter, P.; Lilliestam, J.; Patt, A.; Furler, P.; Steinfeld, A. Drop-in fuels from sunlight and air. Nature 2022, 601, 63−68. (90) Gebald, C.; Wurzbacher, J. A.; Tingaut, P.; Zimmermann, T.; Steinfeld, A. Amine-Based Nanofibrillated Cellulose As Adsorbent for CO2 Capture from Air. Environ. Sci. Technol. 2011, 45, 9101−9108. (91) Gebald, C.; Wurzbacher, J. A.; Tingaut, P.; Steinfeld, A. Stability of Amine-Functionalized Cellulose during Temperature-Vacuum- Swing Cycling for CO2 Capture from Air. Environ. Sci. Technol. 2013, 47, 10063−10070. (92) Romero,M.; Steinfeld, A. Concentrating solar thermal power and thermochemical fuels. Energy Environ. Sci. 2012, 5, 9234−9245. (93) Furler, P.; Scheffe, J.; Marxer, D.; Gorbar, M.; Bonk, A.; Vogt, U.; Steinfeld, A. Thermochemical CO2 splitting via redox cycling of ceria reticulated foam structures with dual-scale porosities. Phys. Chem. Chem. Phys. 2014, 16, 10503−10511. (94) Zoller, S.; Koepf, E.; Nizamian, D.; Stephan, M.; Patané, A.; Haueter, P.; Romero, M.; González-Aguilar, J.; Lieftink, D.; de Wit, E.; et al. A solar tower fuel plant for the thermochemical production of kerosene from H2O and CO2. Joule 2022, 6, 1606−1616. (95)Wei, L.; Pan, Z.; Shi, X.; Esan, O. C.; Li, G.; Qi, H.;Wu, Q.; An, L. Solar-driven thermochemical conversion of H2O and CO2 into sustainable fuels. iScience 2023, 26, 108127. (96) Chen, C.; Jiao, F.; Lu, B.; Liu, T.; Liu, Q.; Jin, H. Challenges and perspectives for solar fuel production from water/carbon dioxide with thermochemical cycles. Carbon Neutrality 2023, 2, 9. (97) Tian, C.; Liu, X.; Liu, C.; Li, S.; Li, Q.; Sun, N.; Gao, K.; Jiang, Z.; Chang, K.; Xuan, Y. Air to fuel: Direct capture of CO2 from air and in- situ solar-driven conversion into syngas via Nix/NaA nanomaterials. Nano Res. 2023, 16, 10899−10912. (98) Hori, Y. Electrochemical CO2 Reduction onMetal Electrodes. In Modern Aspects of Electrochemistry; Vayenas, C. G., White, R. E., Gamboa-Aldeco, M. E., Eds.; Springer New York, 2008; pp 89−189. (99) Lee, M.-Y.; Park, K. T.; Lee, W.; Lim, H.; Kwon, Y.; Kang, S. Current achievements and the future direction of electrochemical CO2 reduction: A short review. Crit. Rev. Environ. Sci. Technol. 2020, 50, 769−815. (100) Bidrawn, F.; Kim, G.; Corre, G.; Irvine, J. T. S.; Vohs, J. M.; Gorte, R. J. Efficient Reduction of CO2 in a Solid Oxide Electrolyzer. Electrochem. Solid-State Lett. 2008, 11, B167. (101) Tezel, E.; Whitten, A.; Yarema, G.; Denecke, R.; McEwen, J.-S.; Nikolla, E. Electrochemical Reduction of CO2 using Solid Oxide Electrolysis Cells: Insights into Catalysis by Nonstoichiometric Mixed Metal Oxides. ACS Catal. 2022, 12, 11456−11471. (102) Hou, X.; Jiang, Y.; Wei, K.; Jiang, C.; Jen, T.-C.; Yao, Y.; Liu, X.; Ma, J.; Irvine, J. T. S. Syngas Production from CO2 and H2O via Solid- Oxide Electrolyzer Cells: Fundamentals, Materials, Degradation, Operating Conditions, and Applications. Chem. Rev. 2024, 124, 5119−5166. (103) Emadi, M.; Barahimi, V.; Croiset, E. Integrated direct air CO2 capture and solid oxide electrolyzer for sustainable chemical production: Case studies of methanol and synthesis fuel. J. CO2 Util. 2025, 96, 103096. (104) Zhu, C.; Song, Y.; Dong, X.; Li, G.; Chen, A.; Chen,W.;Wu, G.; Li, S.; Wei, W.; Sun, Y. Ampere-level CO2 reduction to multicarbon products over a copper gas penetration electrode. Energy Environ. Sci. 2022, 15, 5391−5404. (105) Li, S.; Dong, X.; Wu, G.; Song, Y.; Mao, J.; Chen, A.; Zhu, C.; Li, G.; Wei, Y.; Liu, X.; et al. Ampere-level CO2 electroreduction with single-pass conversion exceeding 85% in acid over silver penetration electrodes. Nat. Commun. 2024, 15, 6101. (106) Li, Z.; Wang, P.; Han, G.; Yang, S.; Roy, S.; Xiang, S.; Jimenez, J. D.; Kondapalli, V. K. R.; Lyu, X.; Li, J.; et al. Ampere-level co- electrosynthesis of formate from CO2 reduction paired with form- aldehyde dehydrogenation reactions. Nat. Commun. 2025, 16, 4850. (107) Cobb, S. J.; Dharani, A. M.; Oliveira, A. R.; Pereira, I. A. C.; Reisner, E. Carboxysome-Inspired Electrocatalysis using Enzymes for the Reduction of CO2 at Low Concentrations. Angew. Chem., Int. Ed. 2023, 62, No. e202218782. (108) Song, H.; Fernández, C. A.; Venkataraman, A.; Brandaõ, V. D.; Dhingra, S. S.; Arora, S. S.; Bhargava, S. S.; Villa, C.M.; Sievers, C.; Nair, S.; Hatzell, M. C. Ethylene Production from Carbonate Using a Bipolar Membrane Electrolysis System. ACS Appl. Energy Mater. 2024, 7, 1224−1233. (109) Xiao, Y. C.; Gabardo, C. M.; Liu, S.; Lee, G.; Zhao, Y.; O’Brien, C. P.; Miao, R. K.; Xu, Y.; Edwards, J. P.; Fan, M.; et al. Direct carbonate electrolysis into pure syngas. EES Catal. 2023, 1, 54−61. (110) Cobb, S. J.; Rodríguez-Jiménez, S.; Reisner, E. Connecting Biological and Synthetic Approaches for Electrocatalytic CO2 Reduction. Angew. Chem., Int. Ed. 2024, 63, No. e202310547. Journal of the American Chemical Society pubs.acs.org/JACS Perspective https://doi.org/10.1021/jacs.5c21750 J. Am. Chem. Soc. 2026, 148, 10267−10285 10282 https://doi.org/10.1016/j.joule.2023.05.022 https://doi.org/10.1016/j.joule.2023.05.022 https://doi.org/10.1021/acsenergylett.9b00975?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1038/s41560-025-01714-y https://doi.org/10.1038/s41560-025-01714-y https://doi.org/10.1002/anie.201506952 https://doi.org/10.1002/anie.201506952 https://doi.org/10.1016/j.seppur.2024.129415 https://doi.org/10.1016/j.seppur.2024.129415 https://doi.org/10.1016/j.jcou.2017.03.008 https://doi.org/10.1016/j.jcou.2017.03.008 https://doi.org/10.1021/acsestengg.4c00503?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acsestengg.4c00503?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acsenergylett.2c01147?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acsenergylett.2c01147?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acsenergylett.2c01147?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1098/rsta.2010.0114 https://doi.org/10.1098/rsta.2010.0114 https://doi.org/10.1098/rsta.2010.0114 https://doi.org/10.1021/ef201875v?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/ef201875v?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.3390/ma16093582 https://doi.org/10.3390/ma16093582 https://doi.org/10.3390/ma16093582 https://doi.org/10.1016/S0360-3199(01)00177-X https://doi.org/10.1016/S0360-3199(01)00177-X https://doi.org/10.1016/j.ijhydene.2012.08.004 https://doi.org/10.1016/j.ijhydene.2012.08.004 https://doi.org/10.1016/j.actamat.2015.10.026 https://doi.org/10.1016/j.actamat.2015.10.026 https://doi.org/10.1016/j.actamat.2015.10.026 https://doi.org/10.1016/j.solener.2014.02.033 https://doi.org/10.1016/j.solener.2014.02.033 https://doi.org/10.1016/j.solener.2014.02.033 https://doi.org/10.1021/acsenergylett.1c00181?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acsenergylett.1c00181?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1038/s41586-021-04174-y https://doi.org/10.1038/s41586-021-04174-y https://doi.org/10.1021/es202223p?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/es202223p?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/es401731p?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/es401731p?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/es401731p?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1039/c2ee21275g https://doi.org/10.1039/c2ee21275g https://doi.org/10.1039/C4CP01172D https://doi.org/10.1039/C4CP01172D https://doi.org/10.1016/j.joule.2022.06.012 https://doi.org/10.1016/j.joule.2022.06.012 https://doi.org/10.1016/j.isci.2023.108127 https://doi.org/10.1016/j.isci.2023.108127 https://doi.org/10.1007/s43979-023-00048-6 https://doi.org/10.1007/s43979-023-00048-6 https://doi.org/10.1007/s43979-023-00048-6 https://doi.org/10.1007/s12274-023-5782-z https://doi.org/10.1007/s12274-023-5782-z https://doi.org/10.1080/10643389.2019.1631991 https://doi.org/10.1080/10643389.2019.1631991 https://doi.org/10.1149/1.2943664 https://doi.org/10.1021/acscatal.2c03398?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acscatal.2c03398?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acscatal.2c03398?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.chemrev.3c00760?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.chemrev.3c00760?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.chemrev.3c00760?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1016/j.jcou.2025.103096 https://doi.org/10.1016/j.jcou.2025.103096 https://doi.org/10.1016/j.jcou.2025.103096 https://doi.org/10.1039/D2EE02121H https://doi.org/10.1039/D2EE02121H https://doi.org/10.1038/s41467-024-50521-8 https://doi.org/10.1038/s41467-024-50521-8 https://doi.org/10.1038/s41467-024-50521-8 https://doi.org/10.1038/s41467-025-60008-9 https://doi.org/10.1038/s41467-025-60008-9 https://doi.org/10.1038/s41467-025-60008-9 https://doi.org/10.1002/anie.202218782 https://doi.org/10.1002/anie.202218782 https://doi.org/10.1021/acsaem.3c02758?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acsaem.3c02758?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1039/D2EY00046F https://doi.org/10.1039/D2EY00046F https://doi.org/10.1002/anie.202310547 https://doi.org/10.1002/anie.202310547 https://doi.org/10.1002/anie.202310547 pubs.acs.org/JACS?ref=pdf https://doi.org/10.1021/jacs.5c21750?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as (111) Chen, Y.; Kan, M.; Yan, S.; Zhang, J.; Liu, K.; Yan, Y.; Guan, A.; Lv, X.; Qian, L.; Zheng, G. Electroreduction of air-level CO2 with high conversion efficiency. Chin. J. Catal. 2022, 43, 1703−1709. (112) Sullivan, I.; Goryachev, A.; Digdaya, I. A.; Li, X.; Atwater, H. A.; Vermaas, D. A.; Xiang, C. Coupling electrochemical CO2 conversion with CO2 capture. Nat. Catal. 2021, 4, 952−958. (113) Stanley, J. S.; Pauker, H. N.; Kuker, E.; Dong, V.; Nielsen, R. J.; Yang, J. Y. Sorbent Mediated Electrocatalytic Reduction of Dilute CO2 to Methane. J. Am. Chem. Soc. 2025, 147, 16099−16106. (114) Gutiérrez-Sánchez, O.; de Mot, B.; Daems, N.; Bulut, M.; Vaes, J.; Pant, D.; Breugelmans, T. Electrochemical Conversion of CO2 from Direct Air Capture Solutions. Energy Fuels 2022, 36, 13115−13123. (115) Zhang, G.; Li, L.; Zhao, Z.-J.; Wang, T.; Gong, J. Electro- chemical Approaches to CO2 Conversion on Copper-Based Catalysts. Acc. Chem. Res. 2023, 4, 212−222. (116) Nitopi, S.; Bertheussen, E.; Scott, S. B.; Liu, X.; Engstfeld, A. K.; Horch, S.; Seger, B.; Stephens, I. E. L.; Chan, K.; Hahn, C.; et al. Progress and Perspectives of Electrochemical CO2 Reduction on Copper in Aqueous Electrolyte. Chem. Rev. 2019, 119, 7610−7672. (117) Chang, F.; Xiao, M.; Miao, R.; Liu, Y.; Ren, M.; Jia, Z.; Han, D.; Yuan, Y.; Bai, Z.; Yang, L. Copper-Based Catalysts for Electrochemical Carbon Dioxide Reduction to Multicarbon Products. Electrochemical Energy Rev. 2022, 5, 4. (118) Rahaman, M.; Andrei, V.; Wright, D.; Lam, E.; Pornrungroj, C.; Bhattacharjee, S.; Pichler, C. M.; Greer, H. F.; Baumberg, J. J.; Reisner, E. Solar-driven liquid multi-carbon fuel production using a standalone perovskite-BiVO4 artificial leaf. Nat. Energy 2023, 8, 629−638. (119) Lee, G.; Rasouli, A. S.; Lee, B.-H.; Zhang, J.; Won, D. H.; Xiao, Y. C.; Edwards, J. P.; Lee, M. G.; Jung, E. D.; Arabyarmohammadi, F.; et al. CO2 electroreduction to multicarbon products from carbonate capture liquid. Joule 2023, 7, 1277−1288. (120) Xiao, Y. C.; Sun, S. S.; Zhao, Y.; Miao, R. K.; Fan, M.; Lee, G.; Chen, Y.; Gabardo, C.M.; Yu, Y.; Qiu, C.; et al. Reactive capture of CO2 via amino acid. Nat. Commun. 2024, 15, 7849. (121) Huang, Y.; Xu, D.; Deng, S.; Lin, M. A hybrid electro- thermochemical device for methane production from the air. Nat. Commun. 2024, 15, 8935. (122) Rabinowitz, J. A.; Kanan, M. W. The future of low-temperature carbon dioxide electrolysis depends on solving one basic problem. Nat. Commun. 2020, 11, 5231. (123) Wills, A. G.; Charvet, S.; Battilocchio, C.; Scarborough, C. C.; Wheelhouse, K. M. P.; Poole, D. L.; Carson, N.; Vantourout, J. C. High- Throughput Electrochemistry: State of the Art, Challenges, and Perspective. Org. Process Res. Dev. 2021, 25, 2587−2600. (124) Fresno, F.; Villar-García, I. J.; Collado, L.; Alfonso-González, E.; Reñones, P.; Barawi, M.; de la Peña O’Shea, V. A. Mechanistic View of the Main Current Issues in Photocatalytic CO2 Reduction. J. Phys. Chem. Lett. 2018, 9, 7192−7204. (125) Uekert, T.; Pichler, C. M.; Schubert, T.; Reisner, E. Solar-driven reforming of solid waste for a sustainable future. Nat. Sustain. 2021, 4, 383−391. (126) Fang, S.; Rahaman, M.; Bharti, J.; Reisner, E.; Robert, M.; Ozin, G. A.; Hu, Y. H. Photocatalytic CO2 reduction. Nat. Rev. Methods Primers 2023, 3, 61. (127) Zhu, S.; Wang, D. Photocatalysis: Basic Principles, Diverse Forms of Implementations and Emerging Scientific Opportunities. Adv. Energy Mater. 2017, 7, 1700841. (128) Miao, Y.; Zhao, Y.; Zhang, S.; Shi, R.; Zhang, T. Strain Engineering: A Boosting Strategy for Photocatalysis. Adv. Mater. 2022, 34, 2200868. (129) Smith, A. M.; Nie, S. Semiconductor Nanocrystals: Structure, Properties, and Band Gap Engineering. Acc. Chem. Res. 2010, 43, 190− 200. (130) Johar, M. A.; Afzal, R. A.; Alazba, A. A.; Manzoor, U. Photocatalysis and Bandgap Engineering Using ZnO Nanocomposites. Adv. Mater. Sci. Eng. 2015, 2015, 1−22. (131) Kim, C.-A.; Wu, J.; Sun, Z.; Li, H. Solar-powered integrated CO2 capture and conversion-A potential paradigm shift for carbon neutrality. Innov. Mater. 2025, 3, 100134. (132)Hou, H.; Yang, D.; Yang,W. Cutting-edge strategies for efficient low-concentration CO2 photoreduction. Mater. Sci. Eng. R Reports 2026, 167, 101136. (133) Nakajima, T.; Tamaki, Y.; Ueno, K.; Kato, E.; Nishikawa, T.; Ohkubo, K.; Yamazaki, Y.; Morimoto, T.; Ishitani, O. Photocatalytic Reduction of Low Concentration of CO2. J. Am. Chem. Soc. 2016, 138, 13818−13821. (134) McQueen, E.; Sakakibara, N.; Kamogawa, K.; Zwijnenburg, M. A.; Tamaki, Y.; Ishitani, O.; Sprick, R. S. Visible-light-responsive hybrid photocatalysts for quantitative conversion of CO2 to highly concentrated formate solutions. Chem. Sci. 2024, 15, 18146−18160. (135) Ma, Y.; Yi, X.; Wang, S.; Li, T.; Tan, B.; Chen, C.; Majima, T.; Waclawik, E. R.; Zhu, H.; Wang, J. Selective photocatalytic CO2 reduction in aerobic environment by microporous Pd-porphyrin- based polymers coated hollow TiO2. Nat. Commun. 2022, 13, 1400. (136) Wu, X.; Li, Y.; Zhang, G.; Chen, H.; Li, J.; Wang, K.; Pan, Y.; Zhao, Y.; Sun, Y.; Xie, Y. Photocatalytic CO2 Conversion of M0.33WO3 Directly from the Air with High Selectivity: Insight into Full Spectrum- Induced Reaction Mechanism. J. Am. Chem. Soc. 2019, 141, 5267− 5274. (137) Yamazaki, Y.; Miyaji, M.; Ishitani, O. Utilization of Low- Concentration CO2 with Molecular Catalysts Assisted by CO2- Capturing Ability of Catalysts, Additives, or Reaction Media. J. Am. Chem. Soc. 2022, 144, 6640−6660. (138) Kumagai, H.; Nishikawa, T.; Koizumi, H.; Yatsu, T.; Sahara, G.; Yamazaki, Y.; Tamaki, Y.; Ishitani, O. Electrocatalytic reduction of low concentration CO2. Chem. Sci. 2019, 10, 1597−1606. (139) Günes, S.; Neugebauer, H.; Sariciftci, N. S. Conjugated Polymer-Based Organic Solar Cells.Chem. Rev. 2007, 107, 1324−1338. (140) Mayer, A. C.; Scully, S. R.; Hardin, B. E.; Rowell, M. W.; McGehee, M. D. Polymer-based solar cells.Mater. Today 2007, 10, 28− 33. (141) Zhang, K.; Gao, Q.; Xu, C.; Zhao, D.; Zhu, Q.; Zhu, Z.;Wang, J.; Liu, C.; Yu, H.; Sun, C.; et al. Current dilemma in photocatalytic CO2 reduction: real solar fuel production or false positive outcomings? Carb. Neutrality 2022, 1, 10. (142) Kamat, P. V.; Jin, S. Semiconductor Photocatalysis: “Tell Us the Complete Story!”. ACS Energy Lett. 2018, 3, 622−623. (143) Yi, L.; Zhao, W.; Huang, Y.; Wu, X.; Wang, J.; Zhang, G. Tungsten bronze Cs0.33WO3 nanorods modified by molybdenum for improved photocatalytic CO2 reduction directly from air. Sci. China Mater. 2020, 63, 2206−2214. (144) Chen, Y.; Ji, G.; Guo, S.; Yu, B.; Zhao, Y.; Wu, Y.; Zhang, H.; Liu, Z.; Han, B.; Liu, Z. Visible-light-driven conversion of CO2 from air to CO using an ionic liquid and a conjugated polymer. Green Chem. 2017, 19, 5777−5781. (145)Wang, L.; Wang, R.; Qiu, T.; Yang, L.; Han, Q.; Shen, Q.; Zhou, X.; Zhou, Y.; Zou, Z. Bismuth Vacancy-Induced Efficient CO2 Photoreduction in BiOCl Directly from Natural Air: A Progressive Step toward Photosynthesis in Nature. Nano Lett. 2021, 21, 10260− 10266. (146) Liao, G.; Ding, G.; Yang, B.; Li, C. Challenges in Photocatalytic Carbon Dioxide Reduction. Precis. Chem. 2024, 2, 49−56. (147) Chakraborty, S.; Peter, S. C. Solar-Fuel Production by Photodriven CO2 Reduction: Facts, Challenges, and Recommenda- tions. ACS Energy Lett. 2025, 10, 2359−2371. (148) Zhang, Y.; Yao, D.; Xia, B.; Jaroniec, M.; Ran, J.; Qiao, S.-Z. Photocatalytic CO2 Reduction: Identification and Elimination of False- Positive Results. ACS Energy Lett. 2022, 7, 1611−1617. (149) Santolin, L.; Riedel, S. L.; Brigham, C. J. Synthetic biology toolkit of Ralstonia eutropha (Cupriavidus necator). Appl. Microbiol. Biotechnol. 2024, 108, 450. (150) Chen, G.-Q. A microbial polyhydroxyalkanoates (PHA) based bio- and materials industry. Chem. Soc. Rev. 2009, 38, 2434−2446. (151) Panich, J.; Fong, B.; Singer, S. W. Metabolic Engineering of Cupriavidus necator H16 for Sustainable Biofuels from CO2. Trends Biotechnol. 2021, 39, 412−424. Journal of the American Chemical Society pubs.acs.org/JACS Perspective https://doi.org/10.1021/jacs.5c21750 J. Am. Chem. Soc. 2026, 148, 10267−10285 10283 https://doi.org/10.1016/S1872-2067(21)63988-8 https://doi.org/10.1016/S1872-2067(21)63988-8 https://doi.org/10.1038/s41929-021-00699-7 https://doi.org/10.1038/s41929-021-00699-7 https://doi.org/10.1021/jacs.4c18303?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/jacs.4c18303?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.energyfuels.2c02623?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.energyfuels.2c02623?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/accountsmr.2c00175?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/accountsmr.2c00175?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.chemrev.8b00705?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.chemrev.8b00705?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1007/s41918-022-00139-5 https://doi.org/10.1007/s41918-022-00139-5 https://doi.org/10.1038/s41560-023-01262-3 https://doi.org/10.1038/s41560-023-01262-3 https://doi.org/10.1016/j.joule.2023.05.003 https://doi.org/10.1016/j.joule.2023.05.003 https://doi.org/10.1038/s41467-024-51908-3 https://doi.org/10.1038/s41467-024-51908-3 https://doi.org/10.1038/s41467-024-53336-9 https://doi.org/10.1038/s41467-024-53336-9 https://doi.org/10.1038/s41467-020-19135-8 https://doi.org/10.1038/s41467-020-19135-8 https://doi.org/10.1021/acs.oprd.1021c00167?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.oprd.1021c00167?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.oprd.1021c00167?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.jpclett.8b02336?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.jpclett.8b02336?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1038/s41893-020-00650-x https://doi.org/10.1038/s41893-020-00650-x https://doi.org/10.1038/s43586-023-00243-w https://doi.org/10.1002/aenm.201700841 https://doi.org/10.1002/aenm.201700841 https://doi.org/10.1002/adma.202200868 https://doi.org/10.1002/adma.202200868 https://doi.org/10.1021/ar9001069?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/ar9001069?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1155/2015/934587 https://doi.org/10.59717/j.xinn-mater.2025.100134 https://doi.org/10.59717/j.xinn-mater.2025.100134 https://doi.org/10.59717/j.xinn-mater.2025.100134 https://doi.org/10.1016/j.mser.2025.101136 https://doi.org/10.1016/j.mser.2025.101136 https://doi.org/10.1021/jacs.6b08824?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/jacs.6b08824?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1039/D4SC05289G https://doi.org/10.1039/D4SC05289G https://doi.org/10.1039/D4SC05289G https://doi.org/10.1038/s41467-022-29102-0 https://doi.org/10.1038/s41467-022-29102-0 https://doi.org/10.1038/s41467-022-29102-0 https://doi.org/10.1021/jacs.8b12928?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/jacs.8b12928?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/jacs.8b12928?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/jacs.2c02245?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/jacs.2c02245?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/jacs.2c02245?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1039/C8SC04124E https://doi.org/10.1039/C8SC04124E https://doi.org/10.1021/cr050149z?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/cr050149z?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1016/S1369-7021(07)70276-6 https://doi.org/10.1007/s43979-022-00011-x https://doi.org/10.1007/s43979-022-00011-x https://doi.org/10.1021/acsenergylett.8b00196?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acsenergylett.8b00196?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1007/s40843-019-1263-1 https://doi.org/10.1007/s40843-019-1263-1 https://doi.org/10.1039/C7GC02346D https://doi.org/10.1039/C7GC02346D https://doi.org/10.1021/acs.nanolett.1c03249?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.nanolett.1c03249?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.nanolett.1c03249?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/prechem.3c00112?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/prechem.3c00112?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acsenergylett.5c00437?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acsenergylett.5c00437?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acsenergylett.5c00437?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acsenergylett.2c00427?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acsenergylett.2c00427?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1007/s00253-024-13284-2 https://doi.org/10.1007/s00253-024-13284-2 https://doi.org/10.1039/b812677c https://doi.org/10.1039/b812677c https://doi.org/10.1016/j.tibtech.2021.01.001 https://doi.org/10.1016/j.tibtech.2021.01.001 pubs.acs.org/JACS?ref=pdf https://doi.org/10.1021/jacs.5c21750?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as (152) Liu, C.; Colón, B. C.; Ziesack, M.; Silver, P. A.; Nocera, D. G. Water splitting biosynthetic system with CO2 reduction efficiencies exceeding photosynthesis. Science 2016, 352, 1210−1213. (153) Torella, J. P.; Gagliardi, C. J.; Chen, J. S.; Bediako, D. K.; Colón, B.; Way, J. C.; Silver, P. A.; Nocera, D. G. Efficient solar-to-fuels production from a hybrid microbial-water-splitting catalyst system. Proc. Nat. Acad. Sci. 2015, 112, 2337−2342. (154) Liu, C.; Colón, B. E.; Silver, P. A.; Nocera, D. G. Solar-powered CO2 reduction by a hybrid biological | inorganic system. J. Photochem. Photobiol., A 2018, 358, 411−415. (155) Dogutan, D. K.; Nocera, D. G. Artificial Photosynthesis at Efficiencies Greatly Exceeding That of Natural Photosynthesis. Acc. Chem. Res. 2019, 52, 3143−3148. (156) Nocera, D. G. Proton-Coupled Electron Transfer: The Engine of Energy Conversion and Storage. J. Am. Chem. Soc. 2022, 144, 1069− 1081. (157) Reece, S. Y.; Hamel, J. A.; Sung, K.; Jarvi, T. D.; Esswein, A. J.; Pijpers, J. J. H.; Nocera, D. G. Wireless Solar Water Splitting Using Silicon-Based Semiconductors and Earth-Abundant Catalysts. Science 2011, 334, 645−648. (158) Nocera, D. G. The Artificial Leaf. Acc. Chem. Res. 2012, 45, 767−776. (159) Li, H.; Opgenorth, P. H.; Wernick, D. G.; Rogers, S.; Wu, T.-Y.; Higashide, W.; Malati, P.; Huo, Y.-X.; Cho, K. M.; Liao, J. C. Integrated Electromicrobial Conversion of CO2 to Higher Alcohols. Science 2012, 335, 1596. (160) Sherbo, R. S.; Silver, P. A.; Nocera, D. G. Riboflavin synthesis from gaseous nitrogen and carbon dioxide by a hybrid inorganic- biological system. Proc. Nat. Acad. Sci. 2022, 119, No. e2210538119. (161) Liu, C.; Sakimoto, K. K.; Colón, B. C.; Silver, P. A.; Nocera, D. G. Ambient nitrogen reduction cycle using a hybrid inorganic- biological system. Proc. Nat. Acad. Sci. 2017, 114, 6450−6455. (162) Nangle, S. N.; Ziesack, M.; Buckley, S.; Trivedi, D.; Loh, D. M.; Nocera, D. G.; Silver, P. A. Valorization of CO2 through lithoautotrophic production of sustainable chemicals in Cupriavidus necator. Metab. Eng. 2020, 62, 207−220. (163) Nangle, S. N.; Sakimoto, K. K.; Silver, P. A.; Nocera, D. G. Biological-inorganic hybrid systems as a generalized platform for chemical production. Curr. Opin. Chem. Biol. 2017, 41, 107−113. (164) https://synhelion.com (accessed Feb 24, 2026). (165) Prats-Salvado, E.; Monnerie, N.; Sattler, C. A techno-economic and environmental evaluation of the integration of direct air capture with hydrogen derivatives production. Int. J. Hydrogen Energy 2025, 140, 1153−1162. (166) https://sun-to-liquid-2.eu (accessed Feb 24, 2026). (167) Xu, B.; Bhawe, Y.; Davis, M. E. Spinel Metal Oxide-Alkali Carbonate-Based, Low-Temperature Thermochemical Cycles for Water Splitting and CO2 Reduction. Chemi. Mater. 2013, 25, 1564− 1571. (168) Xu, B.; Bhawe, Y.; Davis, M. E. Low-temperature, manganese oxide-based, thermochemical water splitting cycle. Proc. Nat. Acad. Sci. 2012, 109, 9260−9264. (169) Charvin, P.; Abanades, S.; Flamant, G.; Lemort, F. Two-step water splitting thermochemical cycle based on iron oxide redox pair for solar hydrogen production. Energy 2007, 32, 1124−1133. (170) Brinkman, L.; Bulfin, B.; Steinfeld, A. Thermochemical Hydrogen Storage via the Reversible Reduction and Oxidation of Metal Oxides. Energy Fuels 2021, 35, 18756−18767. (171) M., Romero, J., Gonzalez-Aguilar, E., Zarza, Concentrating Solar Thermal Power in Energy Conversion, CRC Press, 2nd ed., 2017. (172) Zhu, Q.; Zeng, Y.; Zheng, Y. Overview of CO2 capture and electrolysis technology in molten salts: operational parameters and their effects. Ind. Chem. Mater. 2023, 1, 595−617. (173) Pimlott, D. J. D.; Kim, Y.; Berlinguette, C. P. Reactive Carbon Capture Enables CO2 Electrolysis with Liquid Feedstocks. Acc. Chem. Res. 2024, 57, 1007−1018. (174) Lin, J.; Zhang, Y.; Xu, P.; Chen, L. CO2 electrolysis: Advances and challenges in electrocatalyst engineering and reactor design. Mater. Reports Energy 2023, 3, 100194. (175) Bajada, M. A.; Roy, S.; Warnan, J.; Abdiaziz, K.; Wagner, A.; Roessler, M.M.; Reisner, E. A Precious-Metal-Free Hybrid Electrolyzer for Alcohol Oxidation Coupled to CO2-to-Syngas Conversion. Angew. Chem., Int. Ed. 2020, 59, 15633−15641. (176) Steinlechner, C.; Roesel, A. F.; Oberem, E.; Päpcke, A.; Rockstroh, N.; Gloaguen, F.; Lochbrunner, S.; Ludwig, R.; Spannenberg, A.; Junge, H.; et al. Selective Earth-Abundant System for CO2 Reduction: Comparing Photo- and Electrocatalytic Processes. ACS Catal. 2019, 9, 2091−2100. (177) Rotundo, L.; Gobetto, R.; Nervi, C. Electrochemical CO2 reduction with earth-abundant metal catalysts. Curr. Opin. Green Sustain. Chem. 2021, 31, 100509. (178) Blommaert, M. A.; Aili, D.; Tufa, R. A.; Li, Q.; Smith, W. A.; Vermaas, D. A. Insights and Challenges for Applying Bipolar Membranes in Advanced Electrochemical Energy Systems. ACS Energy Lett. 2021, 6, 2539−2548. (179) Pärnamäe, R.; Mareev, S.; Nikonenko, V.; Melnikov, S.; Sheldeshov, N.; Zabolotskii, V.; Hamelers, H. V. M.; Tedesco, M. Bipolar membranes: A review on principles, latest developments, and applications. J. Membr. Sci. 2021, 617, 118538. (180) Hou, P.; Wang, X.; Wang, Z.; Kang, P. Gas Phase Electrolysis of Carbon Dioxide to Carbon Monoxide Using Nickel Nitride as the Carbon Enrichment Catalyst. ACS Appl. Mater. Interfaces 2018, 10, 38024−38031. (181) Zhao, Y.; Merino-Garcia, I.; Albo, J.; Kaiser, A. A Zero-Gap Gas Phase Photoelectrolyzer for CO2 Reduction with Porous Carbon Supported Photocathodes. ChemSusChem 2024, 17, No. e202400518. (182) Chanda, D.; Lee, S.; Tufa, R. A.; Kim, Y. J.; Xing, R.; Meshesha, M. M.; Demissie, T. B.; Liu, S.; Pant, D.; Santoro, S.; et al. Gas-phase CO2 electrolysis using carbon-derived bismuth nanospheres on porous nickel foam gas diffusion electrode. Int. J. Hydrogen Energy 2024, 56, 1020−1031. (183) Beil, S. B.; Bonnet, S.; Casadevall, C.; Detz, R. J.; Eisenreich, F.; Glover, S. D.; Kerzig, C.; Næsborg, L.; Pullen, S.; Storch, G.; et al. Challenges and Future Perspectives in Photocatalysis: Conclusions from an Interdisciplinary Workshop. JACS Au 2024, 4, 2746−2766. (184) Mohamadpour, F.; Amani, A. M. Photocatalytic systems: reactions, mechanism, and applications. RSC Adv. 2024, 14, 20609− 20645. (185) Liao, G.; Ding, G.; Yang, B.; Li, C. Challenges in Photocatalytic Carbon Dioxide Reduction. Precision Chem. 2024, 2, 49−56. (186) Li, P.; Liu, Y.; Yan, D. Facts and Fictions About Photocatalytic CO2 Reduction to C2+ Products. ChemSusChem 2025, 18, No. e202401174. (187) Wang, H.; Zhang, L.; Chen, Z.; Hu, J.; Li, S.; Wang, Z.; Liu, J.; Wang, X. Semiconductor heterojunction photocatalysts: design, construction, and photocatalytic performances. Chem. Soc. Rev. 2014, 43, 5234−5244. (188) Low, J.; Yu, J.; Jaroniec, M.; Wageh, S.; Al-Ghamdi, A. A. Heterojunction Photocatalysts. Adv. Mater. 2017, 29, 1601694. (189) Di Liberto, G.; Cipriano, L. A.; Tosoni, S.; Pacchioni, G. Rational Design of Semiconductor Heterojunctions for Photocatalysis. Chem. Eur. J. 2021, 27, 13306−13317. (190) Maeda, K. Metal-Complex/Semiconductor Hybrid Photo- catalysts and Photoelectrodes for CO2 Reduction Driven by Visible Light. Adv. Mater. 2019, 31, 1808205. (191) Li, X.; Sun, Y.; Xu, J.; Shao, Y.; Wu, J.; Xu, X.; Pan, Y.; Ju, H.; Zhu, J.; Xie, Y. Selective visible-light-driven photocatalytic CO2 reduction to CH4 mediated by atomically thin CuIn5S8 layers. Nat. Energy 2019, 4, 690−699. (192) Li, X.; Chen, Y.; Tao, Y.; Shen, L.; Xu, Z.; Bian, Z.; Li, H. Challenges of photocatalysis and their coping strategies. Chem Catal. 2022, 2, 1315−1345. (193) Huang, Y.; Shen, M.; Yan, H.; He, Y.; Xu, J.; Zhu, F.; Yang, X.; Ye, Y.-X.; Ouyang, G. Achieving a solar-to-chemical efficiency of 3.6% in ambient conditions by inhibiting interlayer charges transport. Nat. Commun. 2024, 15, 5406. Journal of the American Chemical Society pubs.acs.org/JACS Perspective https://doi.org/10.1021/jacs.5c21750 J. Am. Chem. Soc. 2026, 148, 10267−10285 10284 https://doi.org/10.1126/science.aaf5039 https://doi.org/10.1126/science.aaf5039 https://doi.org/10.1073/pnas.1424872112 https://doi.org/10.1073/pnas.1424872112 https://doi.org/10.1016/j.jphotochem.2017.10.001 https://doi.org/10.1016/j.jphotochem.2017.10.001 https://doi.org/10.1021/acs.accounts.9b00380?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.accounts.9b00380?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/jacs.1c10444?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/jacs.1c10444?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1126/science.1209816 https://doi.org/10.1126/science.1209816 https://doi.org/10.1021/ar2003013?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1126/science.1217643 https://doi.org/10.1126/science.1217643 https://doi.org/10.1073/pnas.2210538119 https://doi.org/10.1073/pnas.2210538119 https://doi.org/10.1073/pnas.2210538119 https://doi.org/10.1073/pnas.1706371114 https://doi.org/10.1073/pnas.1706371114 https://doi.org/10.1016/j.ymben.2020.09.002 https://doi.org/10.1016/j.ymben.2020.09.002 https://doi.org/10.1016/j.ymben.2020.09.002 https://doi.org/10.1016/j.cbpa.2017.10.023 https://doi.org/10.1016/j.cbpa.2017.10.023 https://synhelion.com https://doi.org/10.1016/j.ijhydene.2024.10.026 https://doi.org/10.1016/j.ijhydene.2024.10.026 https://doi.org/10.1016/j.ijhydene.2024.10.026 https://sun-to-liquid-2.eu https://doi.org/10.1021/cm3038747?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/cm3038747?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/cm3038747?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1073/pnas.1206407109 https://doi.org/10.1073/pnas.1206407109 https://doi.org/10.1016/j.energy.2006.07.023 https://doi.org/10.1016/j.energy.2006.07.023 https://doi.org/10.1016/j.energy.2006.07.023 https://doi.org/10.1021/acs.energyfuels.1c02615?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.energyfuels.1c02615?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.energyfuels.1c02615?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1039/D3IM00011G https://doi.org/10.1039/D3IM00011G https://doi.org/10.1039/D3IM00011G https://doi.org/10.1021/acs.accounts.3c00571?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acs.accounts.3c00571?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1016/j.matre.2023.100194 https://doi.org/10.1016/j.matre.2023.100194 https://doi.org/10.1002/anie.202002680 https://doi.org/10.1002/anie.202002680 https://doi.org/10.1021/acscatal.8b03548?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acscatal.8b03548?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1016/j.cogsc.2021.100509 https://doi.org/10.1016/j.cogsc.2021.100509 https://doi.org/10.1021/acsenergylett.1c00618?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acsenergylett.1c00618?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1016/j.memsci.2020.118538 https://doi.org/10.1016/j.memsci.2020.118538 https://doi.org/10.1021/acsami.8b11942?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acsami.8b11942?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/acsami.8b11942?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1002/cssc.202400518 https://doi.org/10.1002/cssc.202400518 https://doi.org/10.1002/cssc.202400518 https://doi.org/10.1016/j.ijhydene.2023.12.234 https://doi.org/10.1016/j.ijhydene.2023.12.234 https://doi.org/10.1016/j.ijhydene.2023.12.234 https://doi.org/10.1021/jacsau.4c00527?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/jacsau.4c00527?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1039/D4RA03259D https://doi.org/10.1039/D4RA03259D https://doi.org/10.1021/prechem.3c00112?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1021/prechem.3c00112?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as https://doi.org/10.1002/cssc.202401174 https://doi.org/10.1002/cssc.202401174 https://doi.org/10.1039/C4CS00126E https://doi.org/10.1039/C4CS00126E https://doi.org/10.1002/adma.201601694 https://doi.org/10.1002/chem.202101764 https://doi.org/10.1002/adma.201808205 https://doi.org/10.1002/adma.201808205 https://doi.org/10.1002/adma.201808205 https://doi.org/10.1038/s41560-019-0431-1 https://doi.org/10.1038/s41560-019-0431-1 https://doi.org/10.1016/j.checat.2022.04.007 https://doi.org/10.1038/s41467-024-49373-z https://doi.org/10.1038/s41467-024-49373-z pubs.acs.org/JACS?ref=pdf https://doi.org/10.1021/jacs.5c21750?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as (194) Brandon, M. P.; Cummins, M.; Deeney, P.; Pryce, M. T. An assessment of photochemical carbon dioxide utilisation technologies using real options. Sustain. Energy Technol. Assess. 2024, 72, 103994. (195) Hanko, E. K. R.; Sherlock, G.; Minton, N. P.; Malys, N. Biosensor-informed engineering of Cupriavidus necator H16 for autotrophic D-mannitol production. Metab. Eng. 2022, 72, 24−34. (196) Härrer, D.; Windhorst, C.; Böhner, N.; Novion Ducassou, J.; Couté, Y.; Gescher, J. Production of acetoin from renewable resources under heterotrophic and mixotrophic conditions. Bioresour. Technol. 2021, 329, 124866. (197) Venkataraman, A.; Song, H.; Brandão, V. D.; Ma, C.; Casajus, M. S.; Fernandez Otero, C. A.; Sievers, C.; Hatzell, M. C.; Bhargava, S. S.; Arora, S. S.; et al. Process and techno-economic analyses of ethylene production by electrochemical reduction of aqueous alkaline carbonates. Nat. Chem. Eng. 2024, 1, 710−723. (198) Soley Salamero, G., Chemisana, D., Santori, G., Cavalcante Quaranta, I.; Murcia López, S. SolDAC: Full Spectrum Solar-Powered Direct CO2 Capture from Air and Conversion in Ethylene. Heat Powered Cycles Conference 2023 (HPCC 2023), The University of Edinburgh: Edinburgh, 2023 . (199) Schaller, R.; Markus, T.; Korte, K.; Gawel, E. Atmospheric CO2 as a resource for renewable energy production: A European energy law appraisal of direct air capture fuels. Rev. Europ. Compar. Int. Environ. Law 2022, 31, 258−267. (200) The Circular Carbon Economy − From Concept to Realization, Report #2, Mission Innovation Think Tank, March 2024 https://mission- innovation.net/wp-content/uploads/2024/03/MI-Think-Tank- Report-Circular-Carbon-Economy.pdf (accessed Feb 24, 2026). Journal of the American Chemical Society pubs.acs.org/JACS Perspective https://doi.org/10.1021/jacs.5c21750 J. Am. Chem. Soc. 2026, 148, 10267−10285 10285 https://doi.org/10.1016/j.seta.2024.103994 https://doi.org/10.1016/j.seta.2024.103994 https://doi.org/10.1016/j.seta.2024.103994 https://doi.org/10.1016/j.ymben.2022.02.003 https://doi.org/10.1016/j.ymben.2022.02.003 https://doi.org/10.1016/j.biortech.2021.124866 https://doi.org/10.1016/j.biortech.2021.124866 https://doi.org/10.1038/s44286-024-00137-y https://doi.org/10.1038/s44286-024-00137-y https://doi.org/10.1038/s44286-024-00137-y https://doi.org/10.5281/zenodo.10927136 https://doi.org/10.5281/zenodo.10927136 https://doi.org/10.1111/reel.12434 https://doi.org/10.1111/reel.12434 https://doi.org/10.1111/reel.12434 https://mission-innovation.net/wp-content/uploads/2024/03/MI-Think-Tank-Report-Circular-Carbon-Economy.pdf https://mission-innovation.net/wp-content/uploads/2024/03/MI-Think-Tank-Report-Circular-Carbon-Economy.pdf https://mission-innovation.net/wp-content/uploads/2024/03/MI-Think-Tank-Report-Circular-Carbon-Economy.pdf pubs.acs.org/JACS?ref=pdf https://doi.org/10.1021/jacs.5c21750?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as