Graphene‐Like Carbon Nitride Nanosheets for Improved Photocatalytic Activities

“Graphitic” (g)‐C 3 N 4 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‐C 3 N 4 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‐C 3 N 4 in air. Compared to the bulk g‐C 3 N 4 , the highly anisotropic 2D‐nanosheets possess a high specific surface area of 306 m 2 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‐C 3 N 4 nanosheets have been remarkably improved in terms of •OH radical generation and photocatalytic hydrogen evolution.