Modulating Tit2gOrbital Occupancy in a Cu/TiO2Composite for Selective Photocatalytic CO2Reduction to CO

Abstract The electronic structure of composites plays a critical role in photocatalytic conversion, whereas it is challenging to modulate the orbital for an efficient catalyst. Herein, we regulated the t 2g orbital occupancy state of Ti to realize efficient CO 2 conversion by adjusting the amount of photo‐deposited Cu in the Cu/TiO 2 composite. For the optimal sample, considerable electrons transfer from the Cu d orbital to the Ti t 2g orbital, as proven by X‐ray absorption spectroscopy. The Raman spectra results also corroborate the electron enrichment on the Ti t 2g orbital. Further theoretical calculations suggested that the orbital energy of the Ti 3d orbital in TiO 2 is declined, contributing to accepting Cu 3d electrons. As a result, the Cu/TiO 2 composite exhibited an extremely high selectivity of 95.9 % for CO, and the productivity was 15.27 μmol g −1 h −1 , which is almost 6 times that of the original TiO 2 . Our work provides a strategy for designing efficient photocatalysis as a function of orbital regulation.