(1. 湖南科技大学 材料科学与工程学院，湘潭411201；
2. 湖南科技大学 高温耐磨材料及制备技术湖南省国防科技重点实验室，湘潭411201；
3. 湖南科技大学 精细聚合物可控制备及功能应用湖南省重点实验室，湘潭411201；
4. 湖南科技大学 新能源储存与转换先进材料湖南省重点实验室，湘潭411201)
摘 要: 通过水热合成和热处理相结合的方法制备p-n型CaFe2O4/WO3异质结复合材料。采用XRD、SEM、TEM、EDS、BET及UV-Vis-DRS对材料结构和性能进行表征和测试，并研究了水溶性染料亚甲基蓝(Methylene blue)的光催化降解。结果表明：相对于单相WO3，p-n型CaFe2O4/WO3复合材料的响应范围明显地扩展到更高波长的可见光区，能高效地实现光催化降解有机染料亚甲基蓝。CaFe2O4/WO3质量比为5%的CaFe2O4/WO3复合材料比表面积为19.7 m2/g，孔径分布在20~150 nm之间；在模拟可见光降解50 mg/L的亚甲基蓝实验中，其在6 h内的降解率达到了90%，重复3次的光催化降解率仍有86%，降解反应速率常数ka为0.180 h-1，显示出优异的光催化降解能力和循环稳定性。降解机理研究表明，WO3和CaFe2O4之间的价带和导带关系满足能级匹配条件，可形成p-n型CaFe2O4/WO3异质结，从而提高复合材料的光催化活性。
关键字: 可见光响应；CaFe2O4/WO3；p-n型异质结；复合半导体；光催化
（1. School of Materials Science and Engineering, Hunan University of Science and Technology, Xiangtan 411201, China;
2. Hunan Provincial Key Defense Laboratory of High Temperature Wear-resisting Materials and Preparation Technology, Hunan University of Science and Technology, Xiangtan 411201, China;
3. Hunan Provincial Key Laboratory of Controllable Preparation and Functional Application of Fine Polymers, Hunan University of Science and Technology, Xiangtan 411201, China;
4. Hunan Provincial Key Laboratory of Advanced Materials for New Energy Storage and Conversion, Hunan University of Science and Technology, Xiangtan 411201, China）
Abstract:The p-CaFe2O4/n-WO3 heterojunction semiconductor composites were prepared by hydrothermal method and heat treatment. The p-CaFe2O4/n-WO3 composites were characterized by XRD, TEM，SEM, EDS, BET and UV-is-DRS. The results show that p-CaFe2O4/n-WO3 composite has red shift of a strong absorption peak to visible region (＞460 nm), showing visible-light responded photocatalysis on methylene blue. The specific surface area of CaFe2O4/WO3composite with 5% in mass ratio is 19.7 m2/g and the BJH pore size distribution focuses on 20-150 nm. During the experiment for simulating visible photodegradation of 50 mg/L methylene blue solution, the photocatalytic degradation rate of CaFe2O4/WO3composite with 5% in mass ratio reaches 90% in 6 h and is still above 86% after three cycles, and the degradation reaction rate constant ka is 0.180 h-1, showing excellent photocatalytic activity and cycle stability. The degradation mechanism studies show that the valence band and guide band relationships between WO3 and CaFe2O4 satisfies the energy level matching conditions and can form p-CaFe2O4/n-WO3 heterojunction, thus improving the photocatalytic activity of the composite.
Key words: visible light response; CaFe2O4/WO3; p-n type heterojunction; compound-semiconductor; photocatalyst
