Structural Distortion of g-C 3 N 4 Induced by a Schiff Base Reaction for Efficient Photocatalytic H 2 Evolution.

Photocatalytic H 2 evolution by water splitting is a promising approach to address the challenges of environmental pollution and energy scarcity. Graphitic carbon nitride (g-C 3 N 4 ) has emerged as a star photocatalyst because of its numerous advantages. To address the limitations of traditional g-C 3 N 4 , namely its inadequate visible light response and rapid recombination of photogenerated carriers, we employed a schiff base reaction to synthesize -C=N- doped g-C 3 N 4 . The introduction of -C=N- groups at the bridging nitrogen sites induced structural distortion in g-C 3 N 4 , facilitating n-π* electronic transitions from the lone pair electrons of nitrogen atom and extending light absorption up to 600 nm. Moreover, the presence of heterogeneous π-conjugated electron distribution effectively traps photogenerated electrons and enhances charge carrier separation. Benefiting from its expanded spectral response range, unique electronic properties, increased specific surface area, the doped g-C 3 N 4 exhibited outstanding photocatalytic H 2 evolution performance of 1050.13 μmol/g/h. The value was 5.9 times greater than the pristine g-C 3 N 4 .