Strengthened H 2 O adsorption and photogenerated carrier separation: surface C-coupled hydroxylation of g-C 3 N 4 photocatalysts for efficient H 2 production

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 12; no. 8; pp. 4854 - 4865
• Main Authors: Hu, Jun, Wu, Lixu, Liu, Hongyin, Sun, Chun, Hussain, Syed Aamir, Jiao, Fei-peng, Liu, Yaochi
• Format: Journal Article
• Language: English
• Published: 20.02.2024
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/D3TA07832A

A photocatalysis based g-C 3 N 4 system is a green and eco-friendly method for hydrogen production, but limited activity of g-C 3 N 4 is undesirable. Presently, most of the modification strategies for the g-C 3 N 4 -based photocatalytic system are centered on doping and heterojunction engineering outside the bulk phase, and little consideration is given to functional group modification within the bulk phase. Herein, surface C-coupled hydroxylated g-C 3 N 4 photocatalysts for efficient H 2 evolution are presented. A C-coupled hydroxylation process is proposed through the reaction of formaldehyde with the unsaturated carbon in the g-C 3 N 4 framework. Compared to pristine g-C 3 N 4 photocatalysts, the surface C-coupled hydroxylated g-C 3 N 4 photocatalyst exhibited over 11.18 times more photocatalytic efficiency for H 2 production, and impressive apparent quantum yield. The experimental findings and theoretical calculations reveal that the morphology, photo-response features, and crystal structure are maintained after the introduction of C-coupled hydroxylation on the g-C 3 N 4 surface, but the H 2 O adsorption and H 2 production efficiency of g-C 3 N 4 are significantly increased due to excellent photoinduced carrier migration efficiency. Therefore, the functional modification of g-C 3 N 4 photocatalysts with C-coupled hydroxylation is highly favorable. This work could offer a new and useful protocol for designing highly efficient functional photocatalysts from a structural modification perspective.