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TiO2/Gd2O3纳米粉体的制备、表征及光催化活性
Preparation, Characterization and Photocatalytic Activities of TiO2/Gd2O3 Nano-powders
【摘要】 利用酸催化的溶胶-凝胶法制备了纯TiO2和Gd3+(0.5wt%)掺杂的TiO2纳米粉体,采用XRD、BET、XPS、紫外-可见漫反射谱(DRS)和表面光电压谱(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Gd3+掺杂对TiO2纳米粉体的光催化活性的影响机制。结果表明,TiO2/Gd2O3纳米粒子对MB溶液的光催化活性提高到纯TiO2的1.5倍。掺杂Gd3+可以强烈抑制TiO2由锐钛矿相向金红石相的转变;阻碍TiO2晶粒的生长;提高高温组织稳定性,改善粉体的表面织构特性;形成光生电子的浅势捕获陷阱,抑制e-/h+复合,这些因素共同作用最终导致TiO2/Gd2O3纳米粉体的光催化活性明显提高。XPS分析结果证实,掺杂Gd3+导致粉体的表面羟基含量降低。由于产生了量子尺寸效应,复合粉体的紫外吸收带边蓝移,光的吸收能力略有降低。
【Abstract】 Pure TiO2 and 0.5wt% Gd3+-doped TiO2 composite nano-particles were prepared by an acid-catalyzed sol-gel method and characterized by XRD, BET, XPS, UV-Vis diffuse reflectance spectroscopy (DRS) and surface photovoltage spetrum (SPS) techniques. The photocatalytic degradation of methylene blue in aqueous solution was used as a probe reaction to evaluate the photocatalytic activity of the synthesized nano-particles. The mechanism of effects of Gd3+-doping on the photocatalytic activity of TiO2 nano-particles was also discussed. The results show that the photocatalytic activity of TiO2/Gd2O3 composite nano-particles is 1.5 times as high as that of pure TiO2. The presence of Gd3+ can inhibit the phase transformation from anatase to rutile, suppress the growth of the crys- tal grains, raise the specific surface area, improve the high temperature stabilization of pores in the composite nano-powders, form the capture traps of the photoproduced electron to inhibit their recombination, resulting in the enhancement of the photocatalytic activity of TiO2/Gd2O3 nano-powders. The results of XPS analysis confirm that Gd3+-doping can lead to the decrease in density of hydroxyl groups on the particle surface. For the composite nanoparticles, a quantum size effect appears, resulting in a blue shift of the absorption edge and a slight decrease in the capability of light absorption.
【Key words】 nanosized titania; Gd3+-doping; photocatalytic activity; environmental cleaning;
- 【文献出处】 无机化学学报 ,Chinese Journal of Inorganic Chemistry , 编辑部邮箱 ,2006年01期
- 【分类号】O614.339;O614.41
- 【被引频次】35
- 【下载频次】550