N-rich carbon nitride (g-C₃N₅) became a promising photocatalyst due to its narrower band gap, larger π-conjugate network, and better visible light responsive hydrogen precipitation activity compared with g-C₃N₄. However, the inherent shortcomings still limited the development of g-C₃N₅. To reasonably address this issue, N defects and surface amino groups were successfully introduced into pristine g-C₃N₅ through facile one-step calcination. Systematical characterizations and theoretical calculation confirmed that the synergy of N defects and the surface-grafted amino group achieved a dual-capture strategy, endowing g-C₃N₅ with higher hydrophilicity and faster photogenerated carrier separation and transfer efficiency. With the modification of urea, the as-prepared samples exhibited a larger specific surface area to further provide more active sites during photocatalysis. The experimental results proved that the photocatalytic hydrogen evolution (PHE) performance of the novel material was significantly enhanced, with the optimal results reaching 5000.6 μmol·h^–1·g^–1, which was 24.5 and 4.5 times higher than that of the pristine g-C₃N₅ and the comparison sample, respectively. The stability and reusability of the N-defected g-C₃N₅ with surface-grafted amino groups were verified by the recycling tests without an obvious decrease after continuous 30 h visible light irradiation. This work provided perspective insight for designing and fabricating the surface functionalized g-C₃N₅ photocatalysts.

中文翻译：

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揭示 N 缺陷 g-C3N5 上表面接枝 −NH2 的双重捕获策略以增强光催化制氢


与 g-C₃N₄ 相比，富氮氮化碳 （g-C₃N₅） 因其更窄的带隙、更大的π共轭网络和更好的可见光响应氢沉淀活性而成为一种很有前途的光催化剂。然而，固有的缺点仍然限制了 g-C₃N₅ 的发展。为了合理地解决这一问题，通过简单的一步煅烧，成功地将 N 缺陷和表面氨基引入原始 g-C₃N₅ 中。系统表征和理论计算证实，N 缺陷和表面接枝氨基的协同作用实现了双重捕获策略，赋予了 g-C₃N₅ 更高的亲水性和更快的光生载流子分离和转移效率。随着尿素的改性，制备的样品表现出更大的比表面积，以进一步在光催化过程中提供更多的活性位点。实验结果表明，新型材料的光催化析氢 （PHE） 性能显著增强，最佳结果达到 5000.6 μmol·h^–1·g^–1，分别是原始 g-C₃N₅ 和对照样品的 24.5 倍和 4.5 倍。通过回收试验验证了表面接枝氨基的 N 缺陷 g-C₃N₅ 在连续 30 h 可见光照射后没有明显降低的稳定性和可重用性。这项工作为设计和制造表面功能化 g-C₃N₅ 光催化剂提供了前瞻性见解。