Hydrothermal synthesis and properties of BiVO_4 photocatalysts

摘要

Bismuth vanadate (BiVO_4) hierarchical spheres were synthesized successfully by a facile hydrothermal approach without any additive by using novel vanadium-based nanosheets as precursors. The results indicated that as-prepared BiVO_4 samples have monoclinic structure with high crystallinity. Scanning electron microscopy images show that the spheres were self-assembled by dozens of nanosheets with good dispersibility and uniform particle size. Meanwhile, the photocatalytic activities of the resulting BiVO_4 were evaluated by photodegradation of methylene blue (MB) under visible light irradiation and exhibited enhanced catalytic efficiency. The excellent performance can be attributed to the high purity, the huge specific surface area, and the novel hierarchical structure. It was also found that the photodegradation of dye pollution is attributed to the oxidation process of the generated hydroxyl radicals and the action of h_(vb)~b, via direct hole oxidation.