Study on the growth mechanism of dispersed monoclinic BiVO4 in hydrothermal process and its photocatalytic activity

In this paper, the monoclinic BiVO4 was successfully prepared, and the preferentially exposed (010) crystal plane was found. The growth mechanism of monoclinic BiVO4 in the hydrothermal process was also deeply analyzed. We explored the phase and structure changes of samples under different preparation conditions via XRD, FT-IR SEM and TEM in order to analyze the growth mechanism of monoclinic BiVO4 from the perspective of thermodynamics and kinetics. Simultaneously, we calculated the forbidden band width of samples prepared at 90 and 180 °C through UV-Vis spectra and analyzed electron hole recombination of different samples through PL spectra. Besides, in order to reveal the photocatalytic activity, photolysis experiment was performed on the samples. The results show that pure monoclinic BiVO4 with flaky structure was successfully prepared at 120 °C. The monoclinic BiVO4 preferentially grew into the flaky structure along the (010) plane, and eventually the block structure was found. Photolysis water experiment was performed on the samples. The samples prepared at 100 °C was found to have the best photocatalytic performance and an O2 production rate of 788.31 µmol/h/g.