High Thermally Stable Mesoporous WO3/TiO2 Heterojunction as a High-Efficient Simulated Solar-Light Photocatalyst

High thermally stable mesoporous WO3/TiO2 heterojunction has been successfully synthesized through a vacuum-induced assistant wet-impregnation method, utilizing tungstophosphoric acid as WO3 precursors and high thermally stable mesoporous TiO2 as hosts, followed by calcination at the high temperature. The structures are characterized in detail by X-ray diffraction, Raman spectra, X-ray photoelectron spectroscopy, N-2 adsorption/desorption isotherms, transmission electron microscopy and UV-visible diffuse reflectance spectra. The results indicate that the heterojunctions between tetragonal phase WO3 and TiO2 are formed, and WO3 nanoparticles uniformly disperse on the surface and fill in the channels of mesoporous TiO2 effectively. The mesoporous WO3/TiO2 heterojunctions exhibit a superior photocatalytic activity in the degradation of 2,4-Dichlorophenol under simulated solar-light irradiation. This enhancement is attributed to their fascinating features including: (1) the ordered mesoporous structure facilitating mass transport, (2) the large surface area offering more active sites, (3) the high crystallinity and special heterojunction benefiting for effective utilization of solar energy and favoring the separation of photogenerated electron-hole pairs. That is further confirmed by electron spin resonance and surface photovoltage spectra.