Visible-Light Driven CO2 Reduction to CO by Co3O4 Supported on Tungsten Oxide

The exploration of support effect and interface effect on a homogeneous–heterogeneous hybrid CO2 reduction photocatalytic system is deficient. Herein, we constructed oxides (WO3, Al2O3, SiO2, TiO2, and CuO) supported Co-based photocatalysts via an incipient wetness impregnation method for visible-light driven CO2 reduction with the assistance of a photosensitizer ([Ru(bpy)3]Cl2) and a sacrificial electron donor (triethanolamine) under mild conditions. Among them, the WO3 supported Co-based photocatalyst (named 1Co/W) exhibited the highest CO generation rate (29.34 μmol h–1) with 81% selectivity and 0.73% apparent quantum yield. Moreover, the unit mass activity of surface Co components was up to 296.35 mmol gCo–1 h–1. Experimental studies and characterization analyses indicated that the superior photocatalytic performance of 1Co/W benefited from the following aspects: (1) the well-matched band structure between 1Co/W and the photosensitizer for charge transfer and the suitable conduction band position for CO2 conversion; (2) the tight interface structure between surface Co active species and WO3 support accelerating the carrier migration kinetics and providing efficient cobalt active sites for CO2 adsorption and activation; and (3) the dispersion and stabilization effect of WO3 on surface Co active species.