Synthesis of g-C_3N_4/BiVO_4 and Its Photocatalytic Performance for Hydrogen Production

摘要

In this study, ultrasonic hybridization was used to improve the photocatalytic efficiency and stability of the g-C_3N_4/BiVO_4 photocatalyst, which was synthesized using Bi(NO_3)_3·5H_2O and NaVO_3 via the hydrothermal method to obtain BiVO_4, and further modified by g-C_3N_4. Moreover, the obtained photocatalyst was studied using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electronmicroscopy, energy-dispersive spectroscopy, transmission electronmicroscopy, Brunauer-Emmett-Teller, ultraviolet-visible spectroscopy and electrochemical impedance spectroscopy. Subsequently, the photocatalytic performance for hydrogen production of the obtained photocatalyst was determined in a photocatalytic reactor under visible light, with methanol as the sacrificial agent and chloroplatinic acid as the promoter. The experimental results showed that the photocatalytic activity of BiVO_4 considerably improved under visible light condition when its surface was modified with g-C_3N_4. When the amount of g-C_3N_4 was 5% of the amount of BiVO_4, the hydrogen production rate was 53.25 μmol/h, which was 77.17 times higher than that of pure BiVO_4. This improved performance can be attributed to the larger specific surface area, the better electron transfer efficiency and the electron-hole pair separation efficiency of g-C_3N_4/BiVO_4. A possible mechanism model for the formation of g-C_3N_4/BiVO_4 composite photocatalyst has also been proposed.