几种纳米结构的CZTS/TiO2异质结薄膜及其高效光催化降解有机污染物的机理研究

In this research project, to systematically research the mechanisms of photocatalysis degradation of organic pollutants, energy level matched semiconductors of p-type narrow band gap CZTS and n-type wide band gap TiO2 are selected for constructing CZTS/TiO2 planar double-layer, core-shell, tubular and rodlike coaxial array heterojunction nanostructures by sol-gel, electrochemical anodization, and hydrothermal methods, respectively. The project aims at exploring new technologies of fabricating novel heterojunction film-photocatalysts, optimum structure of the film-photocatalysts with higher degradation efficiency and application requirements, and researching the heterojunction nanostructure-based photo-generation of excitons, separation of electron-hole pairs, built-in electric field drived transport of free carriers, quantum efficiency of redox reactions, and also the intrinsic mechanism of high-efficient degradation of organic contaminant. Such research programme would have the following advantages: 1) Materials for fabricating the above heterojunction film-photocatalysts are abundant and environmentally friendly; 2) The designed heterojunction nanostructures are simple and easy modeling analysis and testing their photoelectric properties; 3) the simple preparation technology and low-cost processing make the expected results have most promising prospects for applications.

该项目的总体思路是，选用能带匹配的窄带隙p型半导体CZTS和宽带隙n型半导体TiO2，分别采用溶胶-凝胶、阳极氧化和水热法，在透明基底上设计并构筑CZTS/TiO2平面双层、核-壳颗粒以及同轴管（或棒）阵列等不同纳米结构的异质结薄膜；进而系统研究其光催化降解有机污染物的性质与机理。其目的：一则探索制备新型异质结薄膜光催化剂的新方法和新工艺；二则研究其高效降解有机污染物的性能以寻求满足应用需求的最佳结构的薄膜光催化剂；三则基于不同异质结界面结构，考查其中光生电子-空穴对的产生与分离，自由载流子在异质结内建电场驱动下的输运与转移以及光氧化-还原反应的量子转换效率，并深入探究其高效光催化降解有机污染物的内禀机理。该研究方案似具有如下优点：1)拟制备的上述异质结薄膜光催化剂材料来源丰富，环境友好；2)结构设计简单，宜于建模分析和光电子学性能测试；3)工艺简便、成本低，使预期成果的应用研发前景良好。