Microstructure and photocatalytic performance of BiVO4 prepared by hydrothermal method

Monoclinic BiVO4 photocatalyst was hydrothermally synthesized at different pH conditions without surfactant. The microstructure and photocatalytic behavior of as‒prepared samples were characterized by X−ray diffraction, scanning electron microscope, transmission electron microscopy, UV–vis diffuse reflectance spectra, electrochemical workstation and dye degradation experiment. The results show that the pH value had a significant influence on the microstructure and photocatalytic performance of BiVO4. In acid environment, heavy precipitation of tetragonal BiVO4 took place in a short time at room temperature, whereas only amorphous powders formed as the pH value was equal or higher than 7. The monoclinic BiVO4 gradually nucleated and grew at the early stage of synthesis procedure at 180 °C, and finally became the unique crystalline phase. The relationship between microstructure and photocatalytic activity the photocatalyst was well discussed. It is observed that the BiVO4 prepared in the neutral condition (pH 7) exhibited desirable photocatalytic degradation efficiency toward Rhodamine B solution, mainly due to the efficient separation of photogenerated electron‒hole pairs and enhanced visual light absorption during degradation process, which were ascribed to the comprehensive function of high exposed {010} crystal facets, close packed structure, small particle size, and special floating characteristic.