Photoelectrocatalytic properties of Cu2+-doped TiO2 film under visible light

Cu2+-doped TiO2 film on stainless steel substrates was prepared using sol–gel method. Based on XRD and SEM analysis results, the as-prepared film was mainly in anatase phase. The film was smooth and the thickness of the film was about 2 μm. The UV–vis absorption of Cu2+-doped TiO2 was extended to visible range, which is favorable for the utilization of solar light. The photoelectrochemical properties of the samples were investigated via electrochemical impedance spectrum (EIS). The EIS plots demonstrated that the Cu2+-doped TiO2 can be excited under visible light irradiation and the photo-generated electron–hole pairs can be separated efficiently by applying an external bias. The degradation experiments for methylene blue and methyl orange in different processes showed that the photo-response range of TiO2 could be extended by doping Cu2+ ion and the photocatalytic activity of TiO2 could be enhanced with the help of a forward bias.

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► Cu2+-doped TiO2 film on stainless steel substrates was prepared.
► Cu2+-doped TiO2 can be excited under visible light irradiation.
► The photo-generated electron–hole pairs can be separated efficiently by applying an external bias.