Surface P atom grafting of g-C3N4 for improved local spatial charge separation and enhanced photocatalytic H2 production

Abstract

Improving charge separation efficiency and accelerating surface reaction kinetics are two challenging issues for the graphitic carbon nitride (g-C₃N₄) photocatalyst. Surface atom decoration is a facile and efficacious strategy to modulate the electronic structure and then affect the local spatial charge separation of the photocatalyst. Here, we first reported a surface P atom grafting strategy for g-C₃N₄via P–N bond formation to effectively promote the local spatial charge separation and ample reactive sites. The post-calcination process allowed controllable grafting of P–OH at the corner-nitrogen sites in tri-s-triazine of g-C₃N₄, which resulted in an impurity state, and it acted as an electron capture center for local spatial charge separation and reactive sites. Thus, the surface N–P–OH bond modulation of g-C₃N₄ rendered nearly four-fold enhancement in the hydrogen evolution rate. The ability to build pure surface P–N motif modulation presents a promising strategy to realize the precise band engineering of modulated g-C₃N₄. These findings would deepen the understanding of the nonmetal atom decoration-related issues of g-C₃N₄-based materials.