A P/N type compounded Cu2O/TiO2 photo-catalytic membrane for organic pollutant degradation

Abstract

A heterojunction thin film consisting of n-type titanium dioxide (TiO2) and p-type cuprous oxide (Cu2O) was fabricated on an FTO conducting glass. The TiO2 films were grown on the FTO glass by sol–gel and spray pyrolysis methods, and Cu2O was deposited on it via the hydrothermal method. The morphology, crystalline structure, and optical absorption characteristics were studied by scanning electron microscopy, X-ray diffraction, and ultraviolet–visible diffuse reflectance spectrum, respectively. The results show that the surface of the Cu2O/TiO2 film was composed of net and large grains, which contributed to a large specific surface area. The crystal phase of the TiO2 in the Cu2O/TiO2 film remained anatase. The crystal phase of the Cu2O could not be detected as it is found in traces. The Cu2O/TiO2 film had a stronger optical absorption ability than the pure TiO2 film. To investigate catalytic activity, a photocatalytic degradation experiment of the Cu2O/TiO2 film was performed in a homemade thin-layer micro-reactor. The photocatalytic degradation of methylene blue increased with increasing amounts of deposited Cu2O until a maximum limit was reached. The photocatalytic activity might have declined with an increase in Cu2O content. The metallic oxide has the potential to screen other photocatalysts from the UV source.