La掺杂对纳米TiO_2薄膜晶体结构和光催化性能的影响  

Effect of La doping on crystal structure and photocatalytic properties of TiO_2 thin film

作　　者：尹荔松[1] 谭敏[1] 陈永平[1] 李婷[1] 范海陆[1] 

机构地区：[1]中南大学物理科学与技术学院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2008年第4期665-671,共7页Journal of Central South University:Science and Technology

基　　金：中国博士后基金资助项目(20060390878);湖南省博士后基金资助项目(2007RS4024)

摘　　要：采用溶胶-凝胶法在玻璃表面制备La掺杂纳米TiO2薄膜;利用X射线衍射仪(XRD)和原子力显微镜(AFM)对其结构和形貌进行表征;通过对紫外光照射下亚甲基蓝溶液的光催化降解率评价其光催化性能;研究不同掺杂量、热处理温度以及pH值对La掺杂纳米TiO2薄膜光催化性能的影响,并对其光催化的影响机制进行探讨。研究结果表明:适量La掺杂能抑制TiO2由锐钛矿相向金红石相的转变,引起晶格膨胀,导致晶格畸变;La掺杂使TiO2的吸收光谱发生红移,扩展TiO2的光谱吸收范围,有效地提高纳米TiO2薄膜的光催化性能,且光催化反应符合一级动力学方程;La掺杂量(摩尔分数)为0.5%的纳米TiO2薄膜在400℃热处理2h后具有最大的光催化效率98.2%,其光催化效率比纯TiO2薄膜的光催化效率提高约40%。The lanthanum-doped titanium （TiO2） thin films on glass surface were prepared by sol-gel method. The structure and morphology of TiO2 thin films were characterized by X-ray powder diffraction （XRD） and atomic force microscopy （AFM）. The photocatalytic activities were evaluated by degradation of methylene blue under UV light radiation. The influence of variant doping amount of lanthanum （La）, calcination temperature and pH value on the photocatalytic properties of La-doped TiO2 thin film were studied, and the photocatalytic mechanism of La-doped titanium thin films was analyzed. The results show that La doping will restrain the transform of anatase structure to rutile structure, and cause the crystal expansion and the crystal lattice distortion. It also brings in the redshift of light absorption, widens the wavelength absorption range and improves the photocatalytic efficiency effectively. The photocatalytic reactions fix with the first order kinetic equation well. La-doped titanium thin films with 0.5% La annealed at 400 ℃ for 2 h show the best photocatalytic efficiency, which can reach 98.2%. The photocatalytic efficiency of La-doped titanium thin films is improved by about 40% compared to that of pure titanium thin films.

关 键 词：TIO2薄膜 掺杂 光催化 降解率 亚甲基蓝 动力学 

分 类 号：O643.3[理学—物理化学]