Unraveling the\nDual-Capture Strategy in Surface-Grafted\n−NH<sub>2</sub> on N‑Defected g‑C<sub>3</sub>N<sub>5</sub> for Enhanced Photocatalytic Hydrogen Production

N-rich carbon nitride (g-C<sub>3</sub>N<sub>5</sub>)\nbecame a promising\nphotocatalyst due to its narrower band gap, larger π-conjugate\nnetwork, and better visible light responsive hydrogen precipitation\nactivity compared with g-C<sub>3</sub>N<sub>4</sub>. However, the\ninherent shortcomings still limited the development of g-C<sub>3</sub>N<sub>5</sub>. To reasonably address this issue, N defects and surface\namino groups were successfully introduced into pristine g-C<sub>3</sub>N<sub>5</sub> through facile one-step calcination. Systematical characterizations\nand theoretical calculation confirmed that the synergy of N defects\nand the surface-grafted amino group achieved a dual-capture strategy,\nendowing g-C<sub>3</sub>N<sub>5</sub> with higher hydrophilicity and\nfaster photogenerated carrier separation and transfer efficiency.\nWith the modification of urea, the as-prepared samples exhibited a\nlarger specific surface area to further provide more active sites\nduring photocatalysis. The experimental results proved that the photocatalytic\nhydrogen evolution (PHE) performance of the novel material was significantly\nenhanced, with the optimal results reaching 5000.6 μmol·h<sup>–1</sup>·g<sup>–1</sup>, which was 24.5 and 4.5\ntimes higher than that of the pristine g-C<sub>3</sub>N<sub>5</sub> and the comparison sample, respectively. The stability and reusability\nof the N-defected g-C<sub>3</sub>N<sub>5</sub> with surface-grafted\namino groups were verified by the recycling tests without an obvious\ndecrease after continuous 30 h visible light irradiation. This work\nprovided perspective insight for designing and fabricating the surface\nfunctionalized g-C<sub>3</sub>N<sub>5</sub> photocatalysts.