Defect-rich selenium doped graphitic carbon nitride for high-efficiency hydrogen evolution photocatalysis

Graphitic carbon nitride (g-C₃N₄) has been demonstrated as a promising non-metal material for photocatalytic hydrogen evolution (PHE), while its photocatalytic activity is greatly limited due to the narrow visible light response-ability and the intrinsic severe charge deep trapping and recombination effects. Herein, a co-functionalized g-C₃N₄ system by Se doping and nitrogen vacancies modification is developed through a Se vapor-assisted-chemical vapor deposition synthetic strategy. Advanced characterization results revealed that Se dopants promote the visible-light absorption ability of g-C₃N₄, while nitrogen defects-induced shallow trap states are constructive to improving charge separation/transportation efficiency by effectively retarding the detrimental charge deep trapping and recombination. As a result, the synergistic effect of the Se dopants and nitrogen defects leads to a highly efficient PHE performance of g-C₃N₄. The integrated engineering strategy and mechanism understanding provided in this work may offer new insights into developing other novel photocatalysts for various applications.