Preparation of WO3/TiO2/In2O3 composite structures and their enhanced photocatalytic activity under visible light irradiation

Abstract

A novel visible light (λ ≥ 420 nm) active WO3/TiO2/In2O3 composite photocatalyst was prepared by a two-step process. At first, TiO2/In2O3 was synthesized utilizing maleic acid as an organic linker. Afterwards, WO3/TiO2/In2O3 composite heterojunction structure was prepared by the incipient wetness method. The composite was characterized by SEM mapping, high-resolution TEM, BET, UV–Vis diffuse reflectance spectroscopy, XPS and surface acidity measurement. The photocatalytic activity of the composite was evaluated through the decomposition of organic pollutants in gas and aqueous phases. The WO3/TiO2/In2O3 composite demonstrated greatly improved photocatalytic efficiency in compare with TiO2/In2O3 composite and Degussa P25 for the degradation of gaseous 2-propanol and evolution of CO2 and, 1,4-terephthalic acid in aqueous phase under visible light (λ ≥ 420 nm) irradiation. The concentration of WO3 in the composite was optimized to 3.5 mol% WO3/TiO2/In2O3. Based upon these observations, the mechanistic role of WO3 in enhancing the photocatalytic activity of WO3/TiO2/In2O3 has been suggested.