中文摘要：

采用两步溶胶–凝胶法制备了Si掺杂TiO2（Si：TiO2）粉体,通过X射线衍射、热重–差热分析和X射线光电子能谱表征了Si：TiO2粉体样品的晶相及表面结构,以甲基橙为目标物考察了Si掺杂TiO2的光催化活性。研究发现：Si：TiO2粉体在水中降解有机物时,比纯TiO2粉体具有更高的光催化活性;Si：TiO2粉体具有锐钛矿结构,少量Si的引入不仅会抑制TiO2粒径的增大及晶型的转变,而且在Ti原子和Si原子热扩散过程中将导致催化剂的近表面处产生Ti3＋。催化剂外表面存在的Ti4＋与近表面处的Ti3＋形成的电场对电荷的分离作用及Ti3＋和氧空位缺陷的联合作用是Si掺杂TiO2的催化活性大幅度提高的主要原因。

英文摘要：

The Si-doped TiO2（Si：TiO2） powder was prepared by a two-step sol–gel method and its phase composition and surface structure were characterized through X-ray diffraction,thermogravimetry–differential thermal analysis and X-ray photoelectron spec-troscopy.The photocatalytic activity of Si：TiO2 powder was investigated using methyl orange as target compound.The results indi-cate that the Si：TiO2 powder has higher photocatalytic activity than pure TiO2 powder for the degradation of organic matter in water.The Si：TiO2 powder is anatase structure.The introduction of Si into TiO2 not only hinders the increase of particle size and phase transformation,but also leads to generate the Ti3＋ near the catalyst surface during the thermal diffusion process of atoms Si and Ti.The combination of Ti3＋ on near surface with oxygen vacancy defects and the co-existence of Ti4＋ on the catalyst surface and Ti3＋ which play the role of the charge separation on the formation of the charge separation electric field are the real reason for improve-ment of photocatalytic activity of the Si：TiO2.