Artificially imitating the process of photosynthesis, through which some organisms transform CO2 and water into organic molecules, is one of the greatest historical challenges of Science, and today it still is one of the most elusive. The mechanisms of photosynthesis are essentially known, but a device capable of artificially carrying it out competitively has not yet been developed. The central role in artificial photosynthesis is played by the photocatalyst, that is, the substance capable of absorbing energy from light and converting it into chemical energy through the transformation of CO2 molecules into useful products from a chemical point of view (such as carbon monoxide) or energy (such as methane). One of the research lines of the Unit of Photoactivated Processes of IMDEA Energy is the development of these photocatalysts. Recently, researchers from this Unit have developed photocatalysts based on gold and silver nanoparticles supported on titanium dioxide in order to improve the efficiency of the conversion of CO2 into fuels through artificial photosynthesis.* With these materials, activated with UVA light (contained in approximately 5% in sunlight), Selective methane formation has been achieved. On the other hand, when the catalysts are activated with visible light (approximately 40% of the solar light), they are capable of forming, from CO2 and water, carbon monoxide and hydrogen, that is, synthesis gas, which can be used to obtain both fuels and chemicals. Through different techniques that include measurements at the ALBA synchrotron in Barcelona, and in collaboration with the Institute of Catalysis and Petrochemistry of CSIC, the mechanisms that direct the behaviour of these catalysts have been investigated.
(*) P. Reñones, L. Collado, A. Iglesias-Juez, F. E. Oropeza, F. Fresno, V. A. de la Peña O’Shea, Silver-Gold Bimetal Loaded TiO2 Photocatalysts for CO2 Reduction. Industrial & Engineering Chemistry Research, 59 (2020) 9440, https://doi.org/10.1021/acs.iecr.0c01034
More information: Fernando Fresno, Senior Assistant Researcher, Photoactivated Processes Unit. firstname.lastname@example.org