Efficient photocatalytic degradation of acid orange 7 on metal oxide p–n junction composites under visible light

MO(=CuO, Co3O4, NiO)/BiVO4 p–n junction composites were synthesized by urea-precipitation and wet impregnation method. The physicochemical and optical properties of the as-prepared materials were investigated by X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV–visible diffuse reflectance spectra. The photocatalytic performance of the as-prepared materials was investigated for decomposition of azo dye, acid orange 7. The CuO/BiVO4 and Co3O4/BiVO4 p–n junction composite photocatalysts exhibited the higher photocatalytic degradation of acid orange 7 than those of BiVO4 and NiO/BiVO4 as-prepared samples under visible light irradiation. We also discussed the mechanism of enhanced photocatalytic activity of p–n junctioned composites based on their energy band structures.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► p–n junction were synthesized by the urea-precipitation and wet impregnation method. ► CuO/BiVO4 and Co3O4/BiVO4 composite exhibited the high photocatalytic activity. ► Mechanism of enhanced activity of p–n junctioned composites was proposed. ► p–n junction composite can result in efficient charge separation.