Gradual carbon doping of graphitic carbon nitride towards metal-free visible light photocatalytic hydrogen evolution

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 6; no. 31; pp. 15310 - 15319
• Main Authors: Chen, Zhou, Fan, Ting-Ting, Yu, Xiang, Wu, Qiu-Ling, Zhu, Qiu-Hui, Zhang, Li-Zhong, Li, Jian-Hui, Fang, Wei-Ping, Yi, Xiao-Dong
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 2018
• Subjects: absorption; Carbon; Carbon nitride; Carrier mobility; Catalysis; Catalysts; Catalytic activity; Charge transport; Diffusion length; Elongation; Evolution; graphene; Hydrogen; Hydrogen evolution reactions; Hydrogen production; light; Majority carriers; Nitrogen; Oxygen evolution reactions; oxygen production; Photocatalysis; Photocatalysts; Splitting; Vacancies; Water splitting
• ISSN: 2050-7488; 2050-7496; 2050-7496
• DOI: 10.1039/C8TA03303J

Efficient and economical photocatalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are required to replace expensive metal-based catalysts used in water splitting devices. Herein, we have developed an inexpensive route to synthesize a carbon-rich graphitic carbon nitride (C-rich g-C 3 N 4 ) with both nitrogen vacancies and a porous structure, which, as a highly efficient photo-induced water splitting catalyst, can meet current demands. The effects of the porous structure, nitrogen vacancies and rich amount of carbon on the electronic band structure and charge transport of g-C 3 N 4 are systematically elucidated. The C-rich g-C 3 N 4 can not only effectively enhance the absorption of visible light, but can also improve the majority carrier mobility and promote photoelectron transport through the defect-induced mid-gap and multiple conductive carbon rings, thus synergistically elongating the diffusion length and lifetime of the photocarriers. Importantly, the metal-free C-rich g-C 3 N 4 photocatalyst not only demonstrates a higher solar-driven hydrogen production performance, which is over 20.5 times that of pristine g-C 3 N 4 , but also exhibits an outstanding stability with minimal loss of catalytic activity.