UC Berkeley

Research on solar fuels generation has aspired to mimic photosynthesis. Powered by sunlight, photosynthesis converts CO2 and water into C3 intermediates en route to C6 oxygenates (sugars). This study reports an analogous artificial photosynthesis process, inspired by the biological principle of an assembly of coupled microenvironments to achieve multistep, selective chemical conversions to a desired C6 product. Through four codesigned microenvironments working in concert, powered by simulated sunlight, this work demonstrates the conversion of CO2 and water to 2-methyl-2-pentenal, a C6 oxygenate. Specifically, a photovoltaic-driven electrolyzer with a Ag–Cu cathode converts CO2 and water to H2, CO, and C2H4. The products are fed into a photothermocatalytic reactor containing a dual-catalyst bed of Rh-PPh3/SBA-15 and TiO2, which promotes ethylene hydroformylation to propanal, and subsequent propanal aldol condensation to 2-methyl-2-pentenal, a product convertible to hexane, a liquid fuel. This study presents an outline for codesigning assemblies of microenvironments that enable the conversion of CO2 to C6 products.