Mahalakshmi M, Arabindoo Banumathi, Palanichamy M, Murugesan V
Department of Chemistry, Anna University, Chennai 600025, India.
J Nanosci Nanotechnol. 2007 Sep;7(9):3277-85. doi: 10.1166/jnn.2007.689.
TiO2 and Gd3+ doped TiO2 nanoparticles were prepared by sol-gel method and the materials were characterized by XRD, TEM, SEM-EDX, BET, FT-IR, UV-Vis absorption, and Raman spectral analysis. The photocatalytic activity of nano TiO2 and Gd/TiO2 nanoparticles was evaluated using a model pollutant propoxur, a carbamate pesticide, in a batch type UV photoreactor. The results revealed higher photocatalytic activity for Gd/TiO2 nanoparticles than both TiO2 nanoparticles and commercial TiO2 (Degussa P-25). The enhanced photocatalytic activity of Gd/TiO2 relative to TiO2 is attributed to its increased band gap energy as evidenced from the blue shift to shorter wavelength observed in the UV-Vis abso4ption spectra. The recombination rate of photogenerated electron-hole pair decreased due to increase in the band gap, which enhanced the charge transfer efficiency of Gd/TiO2 nanoparticles. Gd3+ with its half filled 7 f subshell facilitated rapid electron transfer at solid-liquid interface by shallowly trapping the electrons. Among the various dopant level of gadolinium, 0.3 wt% Gd/TiO2 nanoparticles showed higher activity than others due to its higher surface area.
采用溶胶 - 凝胶法制备了TiO₂和Gd³⁺掺杂的TiO₂纳米颗粒，并通过X射线衍射（XRD）、透射电子显微镜（TEM）、扫描电子显微镜 - 能谱分析（SEM - EDX）、比表面积分析仪（BET）、傅里叶变换红外光谱（FT - IR）、紫外 - 可见吸收光谱以及拉曼光谱分析对材料进行了表征。在间歇式紫外光反应器中，使用氨基甲酸酯类农药残杀威作为模型污染物，评估了纳米TiO₂和Gd/TiO₂纳米颗粒的光催化活性。结果表明，Gd/TiO₂纳米颗粒的光催化活性高于TiO₂纳米颗粒和商用TiO₂（Degussa P - 25）。Gd/TiO₂相对于TiO₂增强的光催化活性归因于其带隙能量增加，这从紫外 - 可见吸收光谱中观察到的蓝移至较短波长得到证明。由于带隙增加，光生电子 - 空穴对的复合率降低，这提高了Gd/TiO₂纳米颗粒的电荷转移效率。具有半充满7f亚壳层的Gd³⁺通过浅俘获电子促进了固 - 液界面处的快速电子转移。在钆的各种掺杂水平中，0.3 wt%的Gd/TiO₂纳米颗粒由于其较高的比表面积而表现出比其他颗粒更高的活性。
