Cu2O/BiVO4 heterostructures: synthesis and application in simultaneous photocatalytic oxidation of organic dyes and reduction of Cr(VI) under visible light

• Cu2O/BiVO4 photocatalyst was synthesized under mild conditions.
• It shows high catalytic activity for the simultaneous removal of dyes and Cr(VI).
• The degradations of cationic and/or anionic dyes operate under neutral condition.
• A synergistic photoreduction–oxidation mechanism is proposed.

We synthesized Cu2O/BiVO4 composites by growing Cu2O nanoparticles on BiVO4 under mild condition. The optimized composite shows high photocatalytic efficiency in the simultaneous oxidation of organic dyes and reduction of Cr(VI) in neutral media. The XPS results confirm that the Cr(VI) adsorbed on Cu2O/BiVO4 was completely reduced to Cr(III). The photocatalyst can be used for the degradation of cationic or anionic dyes as well as a mixture of them under visible light irradiation. The photocatalytic activity of the composite can be ascribed to the heterojunctions between Cu2O and BiVO4, which facilitate the separation of photogenerated electrons and holes. The work demonstrates that the as-synthesized Cu2O/BiVO4 composite is a promising photocatalyst for the treatment of wastewater that contains organic dyes and Cr(VI) ions.

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