Photocatalytic H₂ and O₂ evolution over tungsten oxide dispersed on silica
2012
Liu, Gang | Wang, Xiuli | Wang, Xiang | Han, Hongxian | Li, Can
Tungsten oxide dispersed on silica (WO₃/SiO₂) as photocatalysts was prepared by sol–gel method and characterized with various techniques, including X-ray diffraction (XRD), UV Raman spectroscopy (UV Raman), UV–vis spectroscopy (UV–vis), N₂-adsorption, X-ray photoelectron spectra (XPS), and high-resolution transmission electron microscopy (HRTEM). The characterization results show that most of tungsten oxide species are present as nanoparticles, which are highly dispersed on the surface of silica. Compared to bulk WO₃, WO₃/SiO₂ exhibits relatively high visible-light-driven O₂ evolution activity in the presence of Fe³⁺ ions as sacrificial reagents. Interestingly, it is found that WO₃/SiO₂ also shows H₂ evolution activity with methanol as sacrificial reagents under UV light. The high photocatalytic O₂ evolution and unexpected H₂ generation properties of WO₃/SiO₂ could be correlated with the presence of highly dispersed WO₃ nanoparticles and their interface W–O–Si like species.
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