稀土掺杂TiO2纳米微粒的合成、表征及光催化活性

采用溶胶-凝胶法制备纯的及掺杂不同量铈的TiO2纳米粒子,利用UV-Vis漫反射光谱及XRD等对所制备样品进行表征.以高压汞灯为光源、甲基橙水溶液的脱色为模型反应,研究了CeO2/TiO2的光催化降解反应活性.实验发现: 掺杂Ce的TiO2纳米粒子反射光谱特性向可见光方向红移到500.nm,比纯的TiO2纳米粒子对光的吸收率高、吸收能力强;掺杂的Ce4 仅有少量进入TiO2晶格中,大部分的Ce4 是以小团簇的CeO2形态均匀地分散在TiO2纳米粒子中或者是覆盖在其表面上.说明掺杂Ce能提高TiO2光催化反应活性,且掺杂Ce摩尔分数最佳值为2.0%.

Synthesis, characterization and photocatalytic activity of rare-earth doped TiO2 nanometer particles

Pure and Ce-doped nano-TiO_2 particles were prepared by a sol-gel process and characterized and explained by UV-Vis and XRD spectra. Being a model reaction,the photocatalytic degradation of methyl orange aqueous solution in the present of CeO_2/TiO_2 nano-particles was investigated with a high pressure mercury lamp as the light source. The results show that rare-earth Ce doped makes the reflective spectral characteristic of nano-TiO_2 move to the visible region with a red shift to 500?nm,and is favorable to enhancing the absorption of visible and UV light of nano-TiO_2. A few Ce 4 doped enter into the crystal lattices of TiO_2,but a lot of Ce 4 doped disperse into TiO_2 or cover onto TiO_2 as the form of CeO_2 with small size. It is indicated that rare-earth Ce doped increases its photocatalytic activity,and the optimum molar fraction of Ce in CeO_2/TiO_2 is 2.0%.