Graphene-Like Carbon Nitride Nanosheets for Improved Photocatalytic Activities

• Published in: Advanced functional materials Vol. 22; no. 22; pp. 4763 - 4770
• Main Authors: Niu, Ping, Zhang, Lili, Liu, Gang, Cheng, Hui-Ming
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 21-11-2012; WILEY‐VCH Verlag
• Subjects: g-C3N4; nanosheets; photocatalysis; thermal oxidation etching
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201200922

“Graphitic” (g)‐C3N4 with a layered structure has the potential of forming graphene‐like nanosheets with unusual physicochemical properties due to weak van der Waals forces between layers. Herein is shown that g‐C3N4 nanosheets with a thickness of around 2 nm can be easily obtained by a simple top‐down strategy, namely, thermal oxidation etching of bulk g‐C3N4 in air. Compared to the bulk g‐C3N4, the highly anisotropic 2D‐nanosheets possess a high specific surface area of 306 m2 g−1, a larger bandgap (by 0.2 eV), improved electron transport ability along the in‐plane direction, and increased lifetime of photoexcited charge carriers because of the quantum confinement effect. As a consequence, the photocatalytic activities of g‐C3N4 nanosheets have been remarkably improved in terms of •OH radical generation and photocatalytic hydrogen evolution.
Graphene‐like C3N4 nanosheets produced by direct thermal oxidative etching of bulk “graphitic”‐C3N4 show superior photocatalytic activities compared to the bulk due to a high specific surface area, a larger bandgap (by 0.2 eV), increased lifetimes of photoexcited charge carriers, and improved electron transport ability.