Boron-doped graphitic carbon nitride nanosheets for enhanced visible light photocatalytic water splitting

A new type of boron-doped graphitic carbon nitride (B-g-C₃N₄) nanosheets was prepared by a benign one-pot thermal polycondensation process. Systematic studies revealed that a B-doping amount of 1 at% into g-C₃N₄ (1at%B-g-C₃N₄) showed the best photocatalytic H₂ evolution activity of 1880 μmol h^-1 g^-1 under visible light irradiation (>400 nm), which is more than 12 times that of the pristine g-C₃N₄ bulk. Detailed characterizations revealed that the high photocatalytic performance could be attributed to the combination of band structure engineering and morphological control. B-doping not only reduces the band gap to absorb more visible light but also exhibits a higher surface area of B-g-C₃N₄ (49.47 m² g^-1) as compared to that of g-C₃N₄ bulk (8.24 m² g^-1), which subsequently improve the photocatalytic performance drastically. This work demonstrates a synergistic strategy to prepare efficient metal-free B-g-C₃N₄ nanosheets as a promising photocatalyst for H₂ evolution under visible light with good stability.