Active site modulation of porous g-C3N4 nanofragment via defect assemblage for enhancing visible-light driven hydrogen evolution. (1st April 2023)

• Record Type: Journal Article
• Authors: Yang, Chengwu; Chen, Yibo; Chen, Tingzhen; Low, Jingxiang; Rajendran, Saravanan; Zeng, Zhiyuan; Zhang, Xinyu; Qin, Jiaqian
• Is Part Of: Fuel. Volume 337(2023)
• Publication Date: 2023-04-01
• Subjects: g-C3N4 -- Structural defect -- Cyano group -- Carbonyl group -- Hydrogen production; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2022.126894
• Languages: English
• ISSNs: 0016-2361

Abstract

Highlights: Cyano group and carbonyl group modified g-C3 N4 nanofragment were fabricated. The modified g-C3 N4 shows porous and ultrathin fragment morphology. Cyano group and carbonyl group efficiently separate charge carriers. Defect assemblage in g-C3 N4 acts as active sites for photocatalytic reaction. The modified g-C3 N4 yields a 10 times enhancement of H2 compared with pure g-C3 N4 . Abstract: Poor light utilization and charge separation are the major factors that retard performance of g-C3 N4 and solar conversion application to green energy. Herein, with the aim to address these issues and enhance photocatalytic hydrogen performance, we design and synthesize the modified g-C3 N4 via defect assemblage of cyano group and carbonyl group. Cyano group and carbonyl group linked in the apex of heptazine unit were loaded into g-C3 N4 framework, endowing g-C3 N4 with extended light response range, tunable band structure and fast charge separation. By experiments analysis and theoretical calculations, the such a defect assemblage can attract photo-charge from other parts of heptazine unit and serve as active sites in photocatalytic process. Therefore, the modified g-C3 N4 material show a ten times higher photocatalytic hydrogen amount than the pristine one and the corresponding apparent quantum efficiency under 405 and 420 nm are 32.30 % and 17.94 %, respectively. In this work, the defect assemblage into g-C3 N4 shows the potential of synergistic effect of different defects on enhancing photocatalytic performance, which can pave a new avenue for the defect engineering in photocatalysis.