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利用UV-vis,FT-IR,XRD,XPS,Raman等手段研究了Ti/Si,Fe/Ti,Fe/Ti/Si复合微粒的表面结构与催化活性.研究表明:Ti/Si复合微粒的光催化活性明显高于TiO_2微粒,TiO_2微粒以晶化度较低的锐钛矿相高度分散在SiO_2网络中,粒径约为10nm;并与SiO_2形成Si—O—Ti桥氧结构;提高了TiO_2微晶的热稳定性、比表面积和表面缺陷;有利于吸附降解有机污染物、半导体光生电子-空穴的分离及提高催化剂的光催化活性.Fe/Ti复合微粒具有Ti—O—Fe网络结构,粒径约为12nm,样品呈晶化度较低的锐钛矿和金红石混晶形式,这种结构有利于促进半导体光生电子-空穴的分离与活性·OH基团的生成;并能在半导体TiO_2中形成杂质中间能级,扩大光响应范围及提高半导体的光催化活性.但是,杂质Fe~(3+)的掺入促进了TiO_2微粒的晶格畸变,晶粒增大.所研究的复合微粒中,Fe/Ti/Si体系具有最高的光催化活性.这种体系兼有Ti/Si,Fe/Ti复合微粒的优点,包含Si—O—Si,Si—O—Ti,Ti—O—Ti,Ti—O—Fe多种网络结构和Fe_2O_3,Fe_3O_4,FeO多种物种,具有很高的比表面积和表面缺陷;大大提高了半导体的光催化活性.是一种极具有实用价值的新型光催化剂.
The surface structure and catalytic activity of Ti / Si, Fe / Ti, Fe / Ti / Si composite particles were studied by means of UV-vis, FT-IR, XRD, XPS and Raman etc. The results show that the light The catalytic activity was significantly higher than that of TiO 2 particles. The TiO 2 particles were highly dispersed in the SiO 2 network with a lower degree of crystallinity. The size of TiO 2 particles was about 10 nm. The TiO 2 particles formed Si-O-Ti bridging oxygen with SiO 2, The thermal stability, the specific surface area and the surface defects of the micro-crystal, which are favorable for the adsorption and degradation of organic pollutants, the separation of the semiconductor photo-generated electron-hole and the improvement of the photocatalytic activity of the catalyst. The Fe / Ti composite particles have a Ti-O-Fe network structure , The particle size of about 12nm, the sample was lower crystallized anatase and rutile mixed crystal form, this structure is conducive to the semiconductor photogenerated electron-hole separation and activity · OH group generation; and in The intermediate level of impurity is formed in the semiconductor TiO 2 to enlarge the light response range and improve the photocatalytic activity of the semiconductor. However, the incorporation of the impurity Fe 3+ promotes the lattice distortion and the grain growth of the TiO 2 particles. In the composite particles, the Fe / Ti / Si system has the highest photocatalytic activity.This system combines Ti / Si, Fe / Ti composite particles, including Si-O-Si, Si-O-Ti, Ti-O-Ti and Ti-O-Fe multiple network structures and Fe2O3, Fe3O4 and FeO species with high ratio Surface area and surface defects; greatly improve the semiconductor photocatalytic activity is a very practical value of the new photocatalyst.