化学学报 ›› 2013, Vol. 71 ›› Issue (05): 793-797.DOI: 10.6023/A12110915 上一篇    下一篇

研究论文

Cu2O/TiO2纳米管阵列异质结的制备及其可见光光电响应性质

张煜, 刘兆阅, 翟锦   

  1. 北京航空航天大学化学与环境学院 仿生智能科学与技术教育部重点实验室 北京 100191
  • 收稿日期:2012-11-13 出版日期:2013-05-14 发布日期:2013-03-01
  • 通讯作者: 刘兆阅,liuzy@buaa.edu.cn;翟锦,zhaijin@buaa.edu.cn; Tel: 010-82318212 E-mail:liuzy@buaa.edu.cn;zhaijin@buaa.edu.cn
  • 基金资助:

    项目受国家自然科学基金(No. 21073009), 博士点基金(No. 30400002011127001), 国家重大基础研究发展规划项目(973项目) (No. 2011CB935704), 国家重大基础研究发展规划项目(973项目) (No. 2012CB720904)和新世纪优秀人才支持计划资助.

Preparation of Cu2O/TiO2 Nanotube Arrays Heterojunction and Their Photoelectrochemical Response in Visible Light

Zhang Yu, Liu Zhaoyue, Zhai Jin   

  1. School of Chemistry and Environment, Beihang University, Beijing 100191, China
  • Received:2012-11-13 Online:2013-05-14 Published:2013-03-01
  • Supported by:

    Project supported by the National Natural Science Foundation of China (No. 21073009), the Ph.D. Programs Foundation of Ministry of Education of China (No. 30400002011127001), the National Research Fund for Fundamental Key Projects (No. 2011CB935704), the National Basic Research Program of China (No. 2012CB720904) and New Century Excellent Talents in University.

采用阳极氧化法制备出结构规整的TiO2纳米管阵列, 然后利用电化学沉积法制备出不同电沉积时间下Cu2O/TiO2纳米管阵列异质结. 通过SEM和UV-vis对样品进行表征, 并对样品的可见光光电转换、光解水等性质进行了测试. 结果表明, Cu2O/TiO2纳米管阵列异质结体系在可见光区域有很强的吸收, TiO2与Cu2O之间形成的p-n结具有单向二级管的性质, 能有效降低光生电子-空穴对的重组, 提高光致电荷分离及电子-空穴对的迁移率. 当电沉积时间为30 min时, Cu2O/TiO2纳米管阵列异质结(Cu2O/TiO2NTs-30)表现出最优的可见光光电响应性质. 虽然与TiO2纳米管相比, Cu2O/TiO2NTs-30的开路电压减少了0.046 V, 但短路电流却提高了4.5倍, 最大吸收波长处光电转换效率提高了近6倍.

关键词: TiO2纳米管阵列, Cu2O, 可见光, 光解水, 光电转换

Self-organized highly oriented TiO2 nanotube arrays have been obtained by anodization of a Ti sheet in fluoride-containing electrolytes.Cu2O/TiO2 nanotube arrays heterojunction have been fabricated by electrochemical methods. The content of Cu2O loaded on the arrays was controlled by varying the electrodeposition time. The samples have been characterized by scanning electron microscopy (SEM) and UV-vis absorption spectrum. In addition, visible photoelectric conversion and photocatalytic water splitting performance of composite electrode materials were characterized under visible light with the measured density of 100 mV·cm-2. The results demonstrated that all Cu2O/TiO2 nanotube arrays heterojunction had a strong absorption in the visible region which suggested that the composite Cu2O/TiO2 nanotubes could make more efficient use of visible light compared with the unmodi?ed TiO2 nanotubes. Simultaneously, p-n heterojunction was formed between Cu2O and TiO2 and the p-n junction was equivalent to a single directional conductive diode that allows electrons to flow from the n-type to the p-type, but the backward flow was prohibited. They could enhance the charges transport and reduce the recombination rate of electrons and holes effectively. Separating the electron-hole pairs in different semiconductors could induce a potential difference at the heterojunction interface. Moreover when the electrodeposition time was 30 min, Cu2O particles were uniform and almost covered the surface of TiO2 nanotubes. Comparing with the composite Cu2O/TiO2 nanotubes prepared by other electrodeposition time, Cu2O/TiO2 nanotube arrays heterojunction fabricated by electroplating for 30 min, noted by Cu2O/TiO2NTs-30, had better performance of photoelectrochemical response in visible light, the visible photoelectric conversion and photocatalytic water splitting efficiency were both the highest. Compared with TiO2 nanotube arrays, though the open-circuit voltage (Voc) of Cu2O/TiO2NTs-30 was -0.629 V and reduced 0.046 V, the short-circuit current density (Isc) enhanced 4.5 times, indicating that there were many more photoelectrons accumulated on the surface of the Cu2O/TiO2 nanotube arrays heterojunction. The improved Isc was also reflected in the increased incident monochromatic photo-to-current conversion efficiency (IPCE), the IPCE response at the maximum absorption wavelength was enhanced almost 6 times.

Key words: TiO2 nanotube arrays, Cu2O, visible light, photo-splitting water, photoelectric conversion