Hollow spherical WO3/TiO2 heterojunction for enhancing photocatalytic performance in visible-light

A novel hollow-sphere structure of tungsten trioxide and titanium dioxide (WO 3 /TiO 2 ) heterojunction was prepared by using a combination of hydrothermal and calcination method. The prepared WO 3 /TiO 2 heterojunction was characterized with scanning electron microscope (SEM), X-ray diffractometer (XRD), Transmission electron microscopy (TEM), X-ray electron spectrometer (XPS), etc. The results showed that 10 % WO 3 /TiO 2 (the mass ratio of W in WO 3 to Ti in TiO 2 was 10 %) has a hollow spherical structure, and the bandgap energy of WO 3 /TiO 2 sample was lower than that of TiO 2 . WO 3 /TiO 2 heterojunction showed an improved photocatalytic performance, compared to pure TiO 2 and WO 3 as well as ZnO and SnO 2 , in degrading a high concentration dye methylene blue (MB) and a micro-organic pollutant metoprolol (MET) under visible-light. MB and MET removal efficiencies could reach 87.8 % and 67.1 %, respectively, within 150 min, by 10 % WO 3 /TiO 2 sample. The relevant photocatalysis mechanisms of the WO 3 /TiO 2 photocatalyst were revealed and discussed. TiO 2 in a heterojunction acted as a photo-generated holes acceptor, effectively decreasing the recombination of photo-generated carriers and improving photocatalytic performance. Our results indicate that the hollow spherical WO 3 /TiO 2 heterojunction is more promising candidate for wastewater treatment in practical applications.