Design of Cu-Cu₂O/g-C₃N₄ nanocomponent photocatalysts for hydrogen evolution under visible light irradiation using water-soluble Erythrosin B dye sensitization

Highlights: • A novel photocatalyst Cu-Cu₂O/g-C₃N₄ was designed, synthesized and characterized. • Cu-Cu₂O/g-C₃N₄ was sensitized by Erythrosin B and a significant enhancement of H₂ evolution rate was achieved. • Electrochemical properties were measured and a possible mechanism of H₂ evolution was proposed. - Abstract: Cu-Cu₂O nanoparticles (NPs) decorated porous graphitic carbon nitride (g-C₃N₄) (Cu-Cu₂O/g-C₃N₄) photocatalysts were prepared. When investment of copper source materials in the experiment increased to 7 wt%, the highest H₂ evolution rate (400 μmol g⁻¹ h⁻¹) was obtained under visible light irradiation in triethanolamine solution. This is about triple of pure g-C₃N₄ (140 μmol g⁻¹ h⁻¹). Moreover, various amount of Erythrosin B dye was added into Cu-Cu₂O/g-C₃N₄ photoreaction solution and a significant enhancement of H₂ production rate was achieved. The highest H₂ production rate was 5000 μmol g⁻¹ h⁻¹ with 5 mg Erythrosin B in photoreaction system. Erythrosin B dye sensitized Cu-Cu₂O/g-C₃N₄ presented stable photocatalytic H₂ evolution ability and no noticeable degradation or change of photocatalyst were detected after six recycles. A possible photocatalytic mechanism of Erythrosin B dye sensitized Cu-Cu₂O/g-C₃N₄ for the enhancement of photocatalytic H₂ evolution is proposed.