Preparation of the TiO2/Graphic Carbon Nitride Core–Shell Array as a Photoanode for Efficient Photoelectrochemical Water Splitting

• Published in: Langmuir Vol. 32; no. 50; pp. 13322 - 13332
• Main Authors: Fan, Xiaoli, Wang, Tao, Gao, Bin, Gong, Hao, Xue, Hairong, Guo, Hu, Song, Li, Xia, Wei, Huang, Xianli, He, Jianping
• Format: Journal Article
• Language: English
• Published: American Chemical Society 20.12.2016
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/acs.langmuir.6b03107

The photoelectrochemical (PEC) oxygen evolution reaction over a photoanode is a promising process for renewable energy. The fascinating properties of graphic carbon nitride (g-CN) in water splitting make the photoelectrode engineering of it for PEC use quite meaningful. In this work, we report the fabrication of the core–shell-structured TiO2/g-CN composite film by hydrothermal growth for TiO2 nanorod arrays and solvothermal growth for the g-CN layer. Herein, TiO2 is used as an effective electron-transfer layer, and g-CN is used as a visible light absorption layer. Different reaction conditions were investigated in order to obtain the uniform TiO2/g-CN nanorod core–shell structure. Outstanding photoelectrochemical performances of the optimized composites were obtained compared to that of pristine TiO2 or g-CN because the high-quality heterojunction between g-CN and TiO2 turned out to effectively reduce the recombination of charge carriers and improve the photoelectric conversion ability. Thus, the photocurrent density under visible light of TiO2/g-CN reached 80.9 μA cm–2, which is 21 times that of g-CN under 0.6 V (vs SCE). Finally, a systematic photoelectrocatalytic mechanism of charge carrier migration and the recombination path in the TiO2/g-CN nanorod core–shell heterojunction was proposed, which can be considered to be a probable explanation of efficient PEC performance.