Regulating COOH Intermediate via Rationally Constructed Surface‐Active Sites of Bi2WO6 for Solar‐Driven CO2‐to‐CO Production

Solar‐driven CO2 reduction holds great promise for sustainable energy, yet the role of atomic active sites in governing intermediate formation and conversion remains poorly understood. Herein, a synergistic strategy using Ni single atoms (SAs) and surface oxygen vacancies (Ov) is reported to regulate the CO2 reduction pathway on the Bi2WO6 photocatalyst. Combining in‐situ techniques and theoretical modeling, the reaction mechanism and the structure‐activity relationship is elucidated. In‐situ X‐ray absorption spectroscopy identifies Bi and Ni as active sites, and in‐situ diffuse reflectance infrared Fourier transform spectroscopy demonstrates that adsorption of H2O and CO2 readily forms CO32− species on the Ov‐rich catalyst. Optimally balancing Ni SAs and Ov lowers the energy barrier for the formation and dehydration of a key COOH intermediate, leading to favorable CO formation and desorption. Consequently, a superior CO production efficiency of 53.49 µmol g‒1 is achieved, surpassing previous reports on Bi2WO6‐based catalysts for gas‐phase CO2 photoreduction.