In Situ Bond Modulation of Graphitic Carbon Nitride to Construct p-n Homojunctions for Enhanced Photocatalytic Hydrogen Production

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• 作者：Guigao Liu ; Guixia Zhao ; Wei Zhou ; Yanyu Liu ; Hong Pang ; Huabin Zhang ; Dong Hao ; Xianguang Meng ; Peng Li ; Tetsuya Kako and Jinhua Ye
• 刊名：Advanced Functional Materials
• 出版年：2016
• 出版时间：October 4, 2016
• 年：2016
• 卷：26
• 期：37
• 页码：6822-6829
• 全文大小：1716K
• ISSN：1616-3028

文摘

Graphitic carbon nitride (g-C₃N₄) has recently emerged as an attractive photocatalyst for solar energy conversion. However, the photocatalytic activities of g-C₃N₄ remain moderate because of the insufficient solar-light absorption and the fast electron–hole recombination. Here, defect-modified g-C₃N₄ (DCN) photocatalysts, which are easily prepared under mild conditions and show much extended light absorption with band gaps decreased from 2.75 to 2.00 eV, are reported. More importantly, cyano terminal CN groups, acting as electron acceptors, are introduced into the DCN sheet edge, which endows the DCN with both n- and p-type conductivities, consequently giving rise to the generation of p–n homojunctions. This homojunction structure is demonstrated to be highly efficient in charge transfer and separation, and results in a fivefold enhanced photocatalytic H₂ evolution activity. The findings deepen the understanding on the defect-related issues of g-C₃N₄-based materials. Additionally, the ability to build homojunction structures by the defect-induced self-functionalization presents a promising strategy to realize precise band engineering of g-C₃N₄ and related polymer semiconductors for more efficient solar energy conversion applications.