image: (a) The process of natural photosynthesis. (b) The process of artificial photosynthesis by decoupling light reaction and dark reaction in this work.
Credit: ©Science China Press
Converting CO2 into CO, CH4, CH3OH, and other compounds through artificial photocatalysis in all weather conditions is a sustainable approach aimed at concurrently mitigating the energy crisis and realizing net CO2 emission. Photogenerated electrons have a lifespan ranging from sub-picoseconds to a few seconds, resulting in the prompt cessation of the photocatalytic reaction upon the termination of illumination. The inconsistency in the availability of solar energy, influenced by factors like daylight duration and weather conditions, creates a significant barrier for the widespread adoption of solar-driven CO2 conversion.
In a new research article titled “Sustainable all-weather CO2 utilization by mimicking natural photosynthesis in a single material” published in National Science Review, a joint team from the Institute of Earth Environment, Chinese Academy of Sciences, University of Science and Technology of China, Institute of Atmospheric Physics, Chinese Academy of Sciences, and Shaanxi Normal University presented a novel concept to decouple light and dark reaction processes by mimicking natural photosynthesis, showcasing the feasibility of achieving sustainable CO2 conversion even in the absence of light.
They prepared a Pt-loaded hexagonal-WO3 as the model catalyst, for the purpose of storing photogenerated electrons and hydrogen atoms under light irradiation in the dark. The unique characteristics of the WO3 carrier—its ability to alternate between valence states (W6+/W5+) and its hexagonal tunnel structures—combined with Pt's proficiency in water splitting and transferring hydrogen atoms onto the h-WO3 surface and tunnel structures, are the key to achieve the decoupling of light and dark reactions for CO2 conversion. When exposed to simulated sunlight for 10 minutes, the catalyst was able to convert CO2 to CH4 in the dark for 10 days, indicating the possibility of a single material promoting CO2 conversion in all-weather conditions. In pursuit of practical applications, the team designed outdoor experimental equipment and conducted continuous 15-day experiments using natural light. Results revealed that the CO2 reduction process remained effective at night and on rainy days, indicating the proposed concept enables round-the-clock and all-weather CO2 conversion. By separating the light and dark reactions, solar-driven CO2 utilization becomes independent of uncertainties related to sunlight availability.
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See the article:
Sustainable all-weather CO2 utilization by mimicking natural photosynthesis in a single material
Natl Sci Rev 2023; doi: 10.1093/nsr/nwad275
https://doi.org/10.1093/nsr/nwad275