Preparation And Characterization Of Tungsten-base Porous Materials

The aim of this work is to synthesize WO₃, WO₃-SiO₂, WO₃-SiO₂-TiO₂compositeaerogel via an ambient pressure drying process. The composite aerogels would to be capcityof visible light photocatalytic activity of WO₃, UV photocatalytic activity of TiO₂andadsorption properties of porous materials, so as to overcome the pore strength of WO₃andTiO₃aerogels network and low photocatlysis efficiency of pure TiO₃aerogel under visiblelight.The WO₃, WO₃-SiO₂, WO₃-SiO₂-TiO₂wet gels were prepared by sol-gel method withsodium tungsten, titanium tetrachloride and water glass as raw materials. Hexamethyldisilazane （HMDS）/hexamethyldisiloxane （HMDSO）/hexane （Hexane） mixed solution wasused as modifcation of WO₃, WO₃-SiO₂wet gel. Trimethylchlorosilane （TMCS）/ethanol（EtOH）/hexane（Hexane） mixed solution were used as modification of WO₃-SiO₂-TiO₂wet gel. The WO₃, WO₃-SiO₂, WO₃-SiO₂-TiO₂composite aerogels were prepared via anambient pressure drying process. The morphology and pore properties of WO₃, WO₃-SiO₂andWO₃-SiO₂-TiO₂composite aerogels were studied by SEM, XRD, FTIR, and BET. Theproperties of adsorption and photocatalytic degradation of rhodamine B were analyzed byspectrophotometer. The results indicate that the obtained WO₃aerogels dried at150℃havethe specific surface area of433to566m²/g and pore volume of0.29to0.77cm³/g. WO₃-SiO₂aerogels dried at150℃have the specific surface area of519to719m²/g and pore volume of1.2to1.9cm³/g. WO₃-SiO₂-TiO₂composite aerogels dried at150℃have the specific surfacearea of565to601m²/g and pore volume1.5to2.9cm³/g. The synergistic adsorption/photocatalysis activity of WO₃-SiO₂, WO₃-SiO₂-TiO₂composite aerogels are excellent. Theirperformances of adsorption and photocatalytic degradation of Rhodamine B were better thanpure SiO₂and pure WO₃aerogels, achieving85%even more.