Alkali-treatment synthesis of bismuth vanadium oxide photocatalysts with different morphologies

The bismuth vanadium oxide photocatalysts with different phases and morphologies were facilely synthesized by the alkali-treatment synthesis method. BiVO4 polyhedrons as the raw materials were firstly prepared by a facile hydrothermal method. With the change of the concentrations of NaOH, the surfaces of the raw BiVO4 polyhedrons became rough and then other phases appeared, such as Bi2O3 regular tetrahedrons, Bi7VO13 sheets and rods, and Bi25VO40 triangle-blocks and cuboids. When the concentration of NaOH was 0.1 ​M, the obtained samples were the composites of the polyhedral BiVO4 and regular tetrahedral Bi2O3, which exhibited the best photocatalytic activity in the degradation of several organic pollutants. From the exploration of the degradation mechanism, it showed that the transfer rate of photogenerated electron–hole pairs on the composites of BiVO4 and Bi2O3 was promoted. The h+, •OH and O2•- played key effect in the degradation process. Furthermore, the bismuth vanadium oxide photocatalysts also showed antibacterial activities towards E. coli.