Controllable synthesis of BiVO4 with a homojunction of (110) and (040) crystal facets for photocatalytic degradation of Rhodamine B

Abstract

BiVO4 with a homojunction of (110) and (040) crystal facets (BiVO4-m) has been prepared by using melamine as the promoting agent assisted with hydrothermal approach. Under visible light irradiation, BiVO4-m displayed a better performance for photocatalytic oxidation of Rhodamine B (RhB), and the rate constant improved about 10 times compared to BiVO4. The great improvement of photocatalytic activity was attributed to the better dispersion of rod-like photocatalyst particles, the enhancement of light-absorption ability, and more O–H active groups on the surface. The formed homojunction of (110) and (040) facets led to the effective separation of photo-generated electrons and holes. The possible photocatalytic mechanism of RhB with BiVO4-m was also discussed in detail. The trapping experiments of active species revealed that the photo-generated holes play an important role in photocatalytic reaction. The contribution of the four main active species for photocatalytic efficiency followed with the order: h+ > · > ·OH > e−.