SiO2 template-modified and Cu-doped BiVO4 with high visible-light photocatalytic performance: Preparation and first-principles study

Cu-BiVO4 photocatalysts with an excellent visible light response were successfully fabricated by modification with a SiO2 template and Cu doping. The SiO2 hard template changes the morphology of BiVO4 from rod to sphere. The structure, chemical composition, and optical and photoelectrochemical properties of the photocatalysts were characterized. The photocatalytic activity was measured through RhB degradation under visible light irradiation. The results indicate that copper is successfully doped in the form of Cu2+ and Cu+. Copper can be used as electron capture traps, which reduces the carrier recombination rate. Compared with other reports, Cu doping is found to greatly improve the ability of BiVO4 to degrade RhB. The crystal phase of BiVO4 is not significantly changed due to Cu doping, and the optimal doping amount is 10%. The RhB degradation rate of the optimal 10% Cu-BiVO4 sample reaches 99.7% within 70 min. Cu-BiVO4 exhibits stable degradation activity, and the photocatalytic kinetics follows a pseudo-first-order equation. ·O2- and h+ play dominant roles in RhB degradation by Cu-BiVO4. The mechanism for the enhancement of the BiVO4 photocatalytic ability was researched with first-principles calculations. The results of band structure and density of states calculations reveal that Cu doping not only promotes electron transitions but also acts as an electron trap to reduce the recombination rate and enhance the efficiency of separation and transfer of photogenerated charge carriers. This work highlights a new way to improve the photocatalytic performance and applications of BiVO4.