Visible-light-enhanced photocatalytic activity of BaTiO3/γ-Al2O3 composite photocatalysts for photodegradation of tetracycline hydrochloride

A polyacrylamide gel method combined with low temperature sintering technology was developed for fabrication of BaTiO3/gamma-Al2O3 composite photocatalysts, which exhibits excellent photocatalytic activity for the degradation of tetracycline hydrochloride (TC-HCl) under simulated sunlight irradiation. The effects of BaTiO3/ gamma-Al2O3 mass percentages, drug concentrations and pH values on the photocatalytic activity of BaTiO3/gamma-Al2O3 composite photocatalysts were investigated. The optimum BaTiO3/gamma-Al2O3 mass percentage, drug concentration and pH value are 5 wt%, 50 mg/L, and 6.77, respectively. The maximum photocatalytic degradation rate of BaTiO3/(5 wt%) gamma-Al2O3 composite photocatalysts for the degradation of TC-HCl was approximately 16.81 times that of gamma-Al2O3. The trapping experiments and reactive oxygen species production experiments proved that reactive hole and hydroxyl radical played major role in drug degradation. The photocatalytic activity enhancement of the BaTiO3/gamma-Al2O3 composite photocatalysts came from the defect states in alumina and the interfacial defects between barium titanate and alumina and the high charge transfer and separation efficiency, which resulted from the type II band arrangement structure of BaTiO3/gamma-Al2O3. The above results reveal that there is a significant potential application for the BaTiO3/gamma-Al2O3 composite as a photocatalyst in the photo degradation of drugs under simulated sunlight irradiation.