【摘要】 利用酸催化的溶胶-凝胶法制备了纯TiO2和低量Yb3+(w=0.125%)掺杂的TiO2复合纳米粉体,采用XRD,BET,XPS,DRS和SPS等技术进行了表征,以亚甲基蓝(MB)的光催化降解为探针反应,评价了其光催化活性,探讨了低量Yb3+掺杂对TiO2纳米粒子光催化活性的影响机制.研究结果表明,0.125%Yb3+掺杂可以显著提高TiO2纳米粒子的光催化活性.低量Yb3+掺杂可以抑制TiO2由锐钛矿相向金红石相的转变,阻碍TiO2晶粒的生长,改善粉体的表面织构特性,提高高温组织稳定性.XPS分析表明,Yb3+掺杂可以导致粉体的表面羟基含量增加.SPS分析表明,Yb3+掺杂能够抑制光生e-/h+复合,改善粒子表面的光吸收性能.与纯TiO2相比,Yb3+掺杂TiO2纳米粒子光催化氧化活性的提高应归因于Yb3+掺杂抑制了e-/h+复合,增加了表面羟基含量,增大了比表面积,增强了样品表面的光吸收能力.更多还原

【Abstract】 Pure TiO2 and 0.125% (w) Yb3+-doped TiO2 composite nano-particles were prepared by an acid-catalyzed sol-gel method and characterized by the techniques such as XPS, XRD, BET, DRS and SPS. The photocatalytic degradation of methylene blue (MB) in aqueous solution was used as a probe reaction to evaluate their photocatalytic activity. The mechanisms of effects of low amount Yb3+-doping on the photo-catalytic activity of the composite nano-particles were also discussed. The results show that 0.125% Yb3+-doping can significantly enhance the photocatalytic activity of TiO2 nano-particles. The presence of low amount of Yb3+ in TiO2 can inhibit the phase transformation from anatase to rutile, suppress the growth of TiO2 grains, raise the specific surface area, and improve the high temperature stabilization of pores in the composite nano-powders as well. The analytical results of XPS indicate that Yb3+-doping can result in the increase in the density of the surface hydroxyl. The analytical results of SPS confirm that Yb3+-doping can inhibit the recombination of the photo-produced electrons and holes, and improve the light absorption prop-erties of the particle surface. Compared with pure TiO2, the enhanced photocatalytic activity of the Yb3+-doped TiO2 nano-powders can be due to the inhibition of the recombination of the photo-produced e-/h+, the increase of the density of the surface hydroxyl and the specific surface area, and the improvement of the light absorption properties of the particle surface.更多还原