催化学报

催化学报 ›› 2007, Vol. 28 ›› Issue (10): 885-889.

• 研究论文 • 上一篇    下一篇

纳米ZnO-TiO2复合半导体的La3+改性及其光催化活性

程刚1,2,周孝德1,李艳2,仝攀瑞2,王理明2   

  1. 1 西安理工大学水利水电学院, 陕西西安 710048; 2 西安工程大学环境与化学工程学院, 陕西西安 710048
  • 收稿日期:2007-10-25 出版日期:2007-10-25 发布日期:2011-10-28

La3+Modification of ZnO-TiO2 Coupled Semiconductors and Their Photocatalytic Activity

CHENG Gang1,2*, ZHOU Xiaode1, LI Yan2, TONG Panrui2, WANG Liming2   

  1. 1 Faculty of Water Resources and Hydraulic Power, Xi′an University of Technology, Xi′an 710048, Shaanxi, China; 2 School of Environment and Chemistry Engineering, Xi′an Polytechnic University, Xi′an 710048, Shaanxi, China
  • Received:2007-10-25 Online:2007-10-25 Published:2011-10-28

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摘要： 采用溶胶-凝胶法对纳米ZnO-TiO2复合半导体进行了La3+改性,用热重-差示扫描量热、扫描电镜、X射线衍射和拉曼光谱分析了La3+/ZnO-TiO2的晶化温度和微晶结构,并以活性艳红K-2BP为模型降解物,在固定催化剂投加量和通气量条件下考察了La3+掺杂量和煅烧温度对La3+/ZnO-TiO2光催化活性的影响. 结果表明, La3+掺杂使ZnO-TiO2晶型转变温度提高,衍射峰蓝移且峰强度减弱,晶粒进一步减小. La3+掺杂量为0.5%, 煅烧温度为500 ℃, 40 min时对活性艳红K-2BP的降解率为100%, 表观反应速率常数k值达到了0.182 min-1, 为不掺La3+的ZnO-TiO2复合半导体的1.4倍.

关键词: 镧, 氧化锌, 氧化钛, 复合半导体, 稀土掺杂, 光催化活性, 活性艳红

Abstract: Modification of nanocrystalline coupled semiconductor ZnO-TiO2 by means of La3+doping using the sol-gel method was investigated. Thermogravimetry-differential scanning calorimetry, scanning electron microscopy,X-raydiffraction, and Raman spectroscopy were employed to analyse the structure and morphology of La3+/ZnO-TiO2. The degradation of reactive red K-2BP was used to evaluate the photocatalytic activity of the catalyst under UV-lamp (253.7 nm, 20 W) irradiation. Effects of La3+doping concentration and calcination temperature on photocatalytic activity were investigated at a fixed photocatalyst amount and air flow rate. The results showed that La3+doping caused an increase in crystal transformation temperature, a strong blue shift of diffraction peaks, and a decrease in grain size. The reactive red K-2BP could be fully degraded within 40 min when La3+doping content was 0.5% and calcination temperature was 500 ℃. Under these conditions, the apparent absorption coefficient reached 0.182 min-1, which was 1.4 times as large as coupled semiconductor ZnO-TiO2.

Key words: lanthanum, zinc oxide, titania, coupled semiconductor, rare-earth doping, photocatalytic activity, reactive red