TiO2 hollow heterophase junction with enhanced pollutant adsorption, light harvesting, and charge separation for photocatalytic degradation of volatile organic compounds

Abstract

The performances of a photocatalyst in volatile organic compound (VOC) adsorption, photon harvesting, and charge separation largely determine its VOC mineralization efficiency. To simultaneously optimize these properties, this work constructed a hollow heterophase junction by coating anatase TiO2 hollow spheres with amorphous TiO2. Toluene and acetone were selected as model VOC pollutants. Results showed that the amorphous TiO2 coating increased the content of micropores and mesopores for the photocatalyst, enhanced the adsorption of toluene and acetone, and improved light absorption. The heterophase junction, formed by the external amorphous TiO2 shell and inner anatase TiO2 shell, reduced the photon energy required for electron excitation and facilitated charge carrier separation. Given these distinct advantages, the material with the hollow heterophase junction realized efficient mineralization of toluene and acetone.