Study on the Photocatalytic Activity of p–n Junction Photocatalyst Cu₂O/TiO₂

p–n junction photocatalyst Cu₂O/TiO₂ was prepared by ball milling through doping Cu₂O into TiO₂ and using H₂O solution as disperser. The p–n junction photocatalyst Cu₂O/TiO₂ was characterized by UV-Vis diffuse reflection spectrum, Scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of the photocatalyst was evaluated by photocatalytic reduction of Cr₂O²⁻ ₇ and photocatalytic oxidation of methyl orange (MO), respectively. The results showed that, for the photocatalytic reduction of Cr₂O²⁻ ₇, the optimum percentage of doped-Cu₂O is 1.0% (weight percentage). The photoreduction activity of the p–n junction Cu₂O/TiO₂ is much higher than that of TiO₂ on the photocatalytic reduction of Cr₂O²⁻ ₇. However, the photooxidation activity of the p–n junction photocatalyst Cu₂O/TiO₂ is much lower than that of TiO₂ on the photocatalytic oxidation of methyl orange (MO). Namely, the p–n junction photocatalyst Cu₂O/TiO₂ has higher photocatalytic reduction activity, but lower photocatalytic oxidation activity. Cu₂O and TiO₂ were coupled highly, forming the p–n junction Cu₂O/TiO₂ photocatalyst. The photocatalytic activity of the p–n junction Cu₂O/TiO₂ was discussed by the p–n junction principle. Effect of ball milling time on the photocatalytic activity of p–n junction photocatalyst Cu₂O/TiO₂ was also investigated.