Copper Deposited on Reduced Titania as Catalyst for the Production of CH4 from Sunlight and Air

Atmospheric CO 2 and H 2 O adsorbed on the photocatalyst surface undergo sunlight‐assisted conversion to solar products that bridge the gaps between artificial and natural photosynthesis. Herein, we report a Lewis acid‐base interaction derived photocatalyst, Cu deposited on reduced titania, that harvests CO 2 and H 2 O from the air and transforms them to CH 4 . Photocatalyst surface studies confirm that coordinately unsaturated Cu atoms and oxygen vacancies are formed that facilitate CO 2 and H 2 O adsorption. The mechanistic studies, combined with tandem secondary ion mass spectroscopy and isotopic labelling, confirm the CH 4 origin from atmosphere‐adsorbed CO 2 and H 2 O. The contributing factors to photocatalyst instability are explored. We expect that this study will have an impact on the widespread application and economic viability of photocatalytic CO 2 reduction.