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 (Cu_3c) increases the coverage of key *CO species, while bicoordinated oxygen (O_2c) controls the migration of *CO species, thereby effectively reducing the energy requirement for *CO dimerization into *OC-CO intermediates (Δ<i>G</i>_{<i>*</i>OC-CO} = -0.56 eV) in the ethanol pathway. This work offers valuable insights for designing photocatalysts that exhibit improved selectivity for C₂₊ fuels.