Modulating Ti t_(2g)Orbital Occupancy in a Cu/TiO2 Composite for Selective Photocatalytic CO2 Reduction to CO

摘要

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 CO2 conversion by adjusting the amount of photo-deposited Cu in the Cu/TiO2 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 TiO2 is declined,contributing to accepting Cu 3d electrons.As a result,the Cu/TiO2 composite exhibited an extremely high selectivity of 95.9 % for CO,and the productivity was 15.27 μmolg~(-1)h~(-1),which is almost 6 times that of the original TiO2.Our work provides a strategy for designing efficient photocatalysis as a function of orbital regulation.