【摘要】 以表面改性法制备出TiO2/SiO2,进而以浸渍法制备出负载型复合半导体材料WO3-TiO2/SiO2,利用XRD、BET、TPR、UVDRS、IR和TPD等技术对材料的表面性质与构造、光响应性能和化学吸附性能进行了表征,并研究了该材料光催化甲烷和水合成甲醇和氢的反应性能.结果表明:载体有效分散表面物种并使其能隙增大;WO3与TiO2复合所形成的组合活性基元可调变吸光带边并促进对甲烷和水的化学吸附;在100℃以上,光激发WO3-TiO2/SiO2表面产生的光生空穴,促使分子吸附态的甲烷解离并向甲醇转化,形成一定的"光-表面-热"协同作用促使反应顺利进行,对甲醇的选择性达到83%以上.更多还原

【Abstract】 TiO₂/SiO₂ were prepared by the chemical modification reaction on SiO₂, then the supported coupled semiconductors WO₃-TiO₂/SiO₂ were prepared by impregnating TiO₂/SiO₂. The gas-phase photocatalytic production of CH₃OH and H₂ from CH₄ and H₂O on WO₃-TiO₂/SiO₂ has been studied using a fixed-bed annular photoreactor under UV irradiation. The surface structure, photon adsorption property and chemisorption ability of WO₃-TiO₂/SiO₂ have been investigated by the techniques of XRD, TPR, BET, UVDRS, IR and TPD. It was showed that the band-gap energy of well-dispersed surface species on SiO₂ can be increased due to the quantum size effect; the interaction between WO₃ and TiO₂, leading to the formation of W-O-Ti bonds, can improve the photon adsorption properties and the chemsorption abilities of CH₄ and H₂O effectively; the "photon-surface-thermal" synergistic action can be formed on WO₃-TiO₂/SiO₂ at temperature higher than 100 ℃ under UV irradiation, which can promote methane adsorption as dissociative states by photoactive O^-, thus WO₃-TiO₂/SiO₂ has the higher photocatalytic activity with the methanol selectivity of more than 83%.更多还原