A facile method for scalable synthesis of ultrathin g-C₃N₄ nanosheets for efficient hydrogen production

2D graphitic carbon nitride (g-C₃N₄) has attracted great attention as one of the rising-star candidates for prominent water-splitting photocatalysts. Here, we report an extremely facile one-step, template-free method to synthesize ultrathin g-C₃N₄ nanosheets (CN-UMF) by thermal polycondensation of urea simply covered with kitchen-available melamine foam (MF). Compared with g-C₃N₄ agglomerates (CN-U) prepared without the covering of MF, the as-synthesized CN-UMF has an average thickness of about 4.5 nm and an enlarged surface area of 150.3 m² g^-1, leading to enhanced visible light absorption and charge carrier separation abilities. Therefore, it is able to serve as an efficient water-splitting photocatalyst to result in an outstanding hydrogen production rate of 5498 μmol g^-1 h^-1. This work provides a new facile strategy for the scalable synthesis of 2D g-C₃N₄ photocatalysts and paves the way for batch and green production of other 2D materials with good performance.