Selective Photocatalytic Conversion of CO2 to Ethanol via Unsaturated Cu–O Domains

Enhancing the selectivity of photocatalytic CO2 reduction to valuable multicarbon (C2+) products remains a significant challenge in green synthetic chemistry. Here, we present a dual-center strategy for metal oxides that boosts the photochemical conversion of CO2 to ethanol by regulating the coordination number of metal and oxygen sites. Notably, CuO catalysts rich in low-coordinated Cu–O domains have achieved nearly perfect ethanol selectivity (96.9%), extraordinary durability (60 h), and a superior yield rate of 30.5 μmol·g–1·h–1, surpassing the performance of many existing photocatalysts in water vapor and CO2. Density functional theory calculations and operando spectroscopic results provide conclusive evidence that tricoordinated copper (Cu3c) increases the coverage of key *CO species, while bicoordinated oxygen (O2c) controls the migration of *CO species, thereby effectively reducing the energy requirement for *CO dimerization into *OC–CO intermediates (ΔG*OC–CO = −0.56 eV) in the ethanol pathway. This work offers valuable insights for designing photocatalysts that exhibit improved selectivity for C2+ fuels.