采用溶胶?凝胶法制备包覆层厚度约为12 nm的高分散性TiO2包覆SiO2(TCS)复合粉末.在此基础上,合成光催化效率显著提高的Cu和Ag掺杂TCS光催化剂.利用X射线衍射仪、X射线光电子能谱仪、紫外?可见分光光度计和光催化降解甲基橙测试等,系统研究包覆和掺杂对TiO2结构及光催化活性的影响规律和相关作用机制.结果表明,TiO2与SiO2的界面可能以Ti-O-Si化学键联结,并通过影响TiO2的结晶过程而抑制TiO2晶粒的长大.通过控制实验条件得到了性能优异的Cu2O-TiO2-SiO2复合粉末,Cu掺杂的作用机制可理解为Cu2O半导体对TiO2的修饰,光催化活性的提高与氧空位和Cu2O有关.相比较,Ag掺杂对TiO2的禁带宽度影响不大,但吸光强度有较大提高.当Ag掺杂量为1.0%时,光催化降解甲基橙效率达到95.7%.%The TiO2-coated SiO2(TCS) nanocatalysts with about 12 nm thickness coating and high dipersity were synthesized by the sol-gel method. Based on the previous experiment, the photocatalytic efficiency of TCS catalysts was enhanced notably by doping Cu and Ag. The effects of coating and doping on the structure and photocatalytic activity of TiO2and the relative mechanism were investigated by XRD, XPS, UV-vis and the photocatalytic degradation experiment of methyl orange. The results show that, the Ti-O-Si bonds between the interface of TiO2and SiO2have an impact on the crystallization process of TiO2and restrain the growth of the grains. Cu2O-TiO2-SiO2composite powder with excellent performance can be synthesized by controlling the experimental conditions. The reinforcement mechanism of doping Cu can be ascribed to the modification of Cu2O semiconductor to TiO2. The increasing of photocatalytic property is related to the oxygen vacancy and Cu2O particles. Doping Ag cannot change the width of the forbidden band but can improve the intensity of light absorption, and the photocatalytic degradation efficiency is 95.7% after doping 1.0%Ag.
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