Visible-light-induced dendritic BiVO4/TiO2 composite photocatalysts for advanced oxidation process

Visible-light-induced dendritic BiVO4/TiO2 photocatalysts have been successfully synthesized via a composite hydrothermal and sol-gel method. Evaluated by the degradation of methylene blue (MB) under visible-light irradiation (420 nm < λ < 800 nm), the sample with ratio of BiVO4/TiO2 (mass ratio) equal to 60% prepared at 400 °C exhibited the best photocatalytic activity. The appropriate band gap (BiVO4 provided) availed the absorption of visible light and the larger surface area (TiO2 provided) enhanced the adsorption ability towards the pollutants, resulting in the high separation ratio of the electrons and holes generated. Through further detecting the degradation mechanism, it was proposed a new idea that the best activity mainly depended on the synergistic effect of photocatalysis and photosensitization. The active species generated in the degradation processes were mainly derived from BiVO4 and MB, while TiO2 was just the transporter of charge carriers. Some evidence has been provided to support this conclusion in detail. These results would be useful to develop highly efficient photocatalysts and helpful to reveal the degradation mechanism clearly.