Prof. Dr. Erwin Reisner, University of Cambridge, UK

Sunlight-Powered Circular Carbon Chemistry

The design and construction of prototype solar devices for the direct valorisation of carbon dioxide, biomass and plastic waste streams into renewable fuels and higher-value chemicals will be presented. Standalone photoelectrochemical cells and artificial leaves based on integrated lead halide perovskite-BiVO₄ tandem light absorber architectures with immobilised synthetic and biological catalysts have been created for solar CO₂ reduction to produce syngas (CO and H₂), formate or ethanol fuel coupled to O₂ evolution from water oxidation. Photocatalyst sheets assembled from immobilised semiconductor powders with (bio)molecular catalysts can cleanly produce formate and acetate. Replacing water oxidation in traditional artificial photosynthesis by waste oxidation provides thermodynamic, kinetic and economic advantages. This solar reforming approach can readily couple CO2 reduction, including atmospheric CO2, with biomass and plastic waste up-cycling using semiconductor particles and photoelectrochemical devices. Thus, the concept and prospect of integrated solar chemistry for artificial photosynthesis and solar reforming will be discussed, including an outlook on advanced strategies to improve light management in such devices with the ultimate goal to achieve superior performance than indirectly coupled photovoltaic-electrolyser technology.