Preparation of BiOBr/BiVO4 composite and its application for photocatalytic degradation under visible light

BiOBr/BiVO4 heterojunction photocatalysts were synthesised via facile hydrothermal methods and mixed by ultrasonic treatment. The as-prepared samples were characterised by X-ray diffraction, Fourier transform infrared spectra, scanning electron microscopy, transmission electron microscopy and UV–vis diffuse reflection spectrometry. The photocatalytic activity of the samples was evaluated by degradation of Rhodamine B (RhB) under visible light irradiation (400 nm u003c λ u003c 580 nm). As a result, the as-prepared BiOBr/BiVO4 composites showed much higher photocatalytic activity for degradation of RhB as compared to many BiOBr and BiVO4-based photocatalysts. For example, the sample with a BiOBr/BiVO4 ratio of 1:1 showed the highest degradation ratio of 97%, which could stay over 84% after 15 cycles. This excellent photocatalytic activity could be attributed to the BiOBr/BiVO4 heterojunction interface that effectively narrowed the band gap and promoted the separation of photogenerated electron–hole pairs.