Fe~(3+)及Ce~(3+)掺杂对TiO_2纳米粒子性能的影响

以溶胶-凝胶法制备纯的和分别掺杂Fe3+、Ce3+的TiO2纳米粒子,以橙黄IV的光催化氧化评价纳米粒子的紫外光与可见光活性,利用TG-DSC、XRD、BET及UV-Vis吸收光谱考察掺杂对TiO2的相变、粒径、比表面积及光吸收性能的影响,在归一化条件下探讨Fe3+及Ce3+掺杂对TiO2活性和表面性质产生影响的机制。结果表明:Fe3+及Ce3+的最佳掺杂量分别为0.2%和0.04%;Ce3+抑制TiO2由锐钛矿向金红石转变以及改善TiO2高温组织稳定性的能力均明显大于Fe3+;Fe3+和Ce3+掺杂均能提高TiO2的紫外光活性并扩展TiO2的光响应范围,但光生电子与空穴复合以及光腐蚀使它们对TiO2可见光活性的提高并不显著。Fe3+和Ce3+的半径及其相应氧化物的性质决定了两者对TiO2性能的不同影响。

Effects of Fe3+ and Ce3+ Doping on Properties of TiO2 Nanoparticles

Pure and Fe3+ , Ce3+ respectively doped TiO2 nanoparticles were prepared by sol -gel method. Photocatalytic oxidation of Orange IV was taken to evaluate UV and Vis light activity of nanoparticles. TG-DSC, XRD, BET and UV-Vis absorption spectra were employed to investigate the effects of doping on phase transformation, crystallite size, specific surface area and light absorption capacity of TiO2. Effect mechanisms of Fe3+ and Ce3+ doping on activity and surface property of TiO2 were discussed under the uniform condition. Results showed that the optimum doping concentrations of Fe3+ and Ce3+ were 0.2% and 0.04% respectively. Inhibiting ability to the transformation from anatase TiO2 to rutile TiO2 and improving ability to high temperature structure stability of TiO2 of Ce3+ were conspicuous than that of Fe3+. Although Fe3+ doping and Ce3+ doping could both not only enhance UV light activity but also extend the light response scope of TiO2, which had no effect on improving Vis light activity of TiO2 because of recombination of photoinduced electron-hole pairs as well as photocorrosion. Radius and relevant oxide properties were primarily responsible for their different acting mechanisms of Fe3+ and Ce3+.