Abstract:

Mesoporous tungsten oxides were prepared by a hard templating method using mesoporous silica dioxide (KIT-6) as the hard template, silicotungstic acid (H4O40SiW12·nH2O) as the source of tungsten and by removing silica dioxide with HF. The mesoporous tungsten oxides were characterized by X-ray diffraction (XRD), energy dispersive X-ray(EDX), high resolution transmission electron microscopy (HRTEM), and nitrogen adsorption-desorption isotherms. The influences of the mixing ratio of the silicotungstic acid and mesoporous silica, the calcination temperature of the mixture, and different dispersants on the preparation of the mesoporous tungsten oxides was investigated. Results showed that mesoporous tungsten oxides could be obtained at calcination temperatures of 600-750 ℃ and that mixing mass ratios of silicotungstic acid and mesoporous silica (m(WO3)/m(SiO2)) should be 3:1-4:1. Larger surface area and pore volume were obtained for the mesoporous tungsten oxide when using ethanol instead of distilled water as dispersant.

Key words: Mesoporous material, Tungsten oxide, Silicon dioxide, Hard templating method