Oxygen vacancy regulation on tungsten oxides with specific exposed facets for enhanced visible-light-driven photocatalytic oxidation

Introduced oxygen vacancy on WO₃ with specific exposed facets was prepared through facile solvothermal treatment and different cooling methods. We demonstrated that the density of oxygen defects could be regulated by different cooling methods and speculated that oxygen vacancy with appropriate concentration range could promote photocatalytic activity through suppressing the recombination of photo-induced carriers. The specific exposed facets with higher oxidation efficiency were prepared by solvothermal reaction. WO₃-A treated by air cooling exhibits the best photocatalytic oxygen evolution rate at 500 μmol g^-1 h^-1 using AgNO₃ as sacrifice agent under visible light (λ > 400 nm) without any co-catalysts, which is about 2 times higher than WO₃-N without oxygen defects. This strategy, using different cooling methods to regulate oxygen vacancy concentration on tungsten oxides, could contribute to the design of other high efficiency photocatalysts.