Photoinduced Metastable Asymmetric Cu Single Atoms for Photoreduction of CO2 to Ethylene

Abstract Metastable structures are promising candidates for efficient catalysis owing to abundant active electronic states, strong electronic coupling with reactants, and energetic preference. Exerting the value of metastable structures while evading the difficulty in direct synthesis remains challenging. Herein, it is reported that light irradiation enables the generation and maintenance of the metastable state over copper single atoms for efficient carbon dioxide reduction. Under irradiation with light, photogenerated electrons transit to Cu‐3 d orbits and initiate d ‐orbital rearrangement. The initial symmetric Cu 1 ─O 4 coordination converts to the metastable asymmetric structure of Cu 1 ─O 2+1 , and is reversibly restored after removing the light. The photoinduced metastable intermediate of Cu 1 ─O 2+1 promotes the Cu single‐atom catalyst to deliver an ethylene yield rate of 60.4 µmol g cat. −1 h −1 . Mechanistic studies reveal that Cu 1 ─O 2+1 possesses stronger adsorption capability for reactants and intermediates. The reaction energy barrier over Cu 1 ─O 2+1 also shows an obvious decline compared to that over Cu 1 ─O 4 .