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• The carboxyl group with electron-withdrawing effect was grafted on the surface of graphite carbon nitride. • The electron-withdrawing effect can promote the separation and migration of carriers to improve photocatalytic performance. • The performance achieved 52 times enhancement with an apparent quantum yield of 15.7 % at 420 nm. Graphitic carbon nitride (g-C 3 N 4) has recently emerged as a promising candidate for photocatalytic hydrogen evolution, but only showed limited activity owing to its sluggish photogenerated carriers separation and migration. Herein, the carboxyl-functionalized g-C 3 N 4 (O CN) was synthesized by a grafting post-treatment method to alleviate the negative influences from this intrinsic drawback. As a result, the surface carboxyl groups greatly improve charge carrier dynamics to suppress carriers recombination via the driving force originated from its electron-withdrawing effects. The resultant O CN exhibits 52 times higher hydrogen evolution rate than the pristine, and possesses a high apparent quantum yield (AQY) of 15.7 % at 420 ± 15 nm. This work deepens the understanding of the surface group related modifications for photocatalytic materials, further providing a promising approach for rational design of photocatalysts with highly efficient solar energy conversion. [ABSTRACT FROM AUTHOR]