The precise molecular tunability strategy is deemed to have great potential to improve the photocatalytic performance of metal-free photocatalysts for applying in hydrogen evolution but remains a formidable task. We herein cover a logical design for integrating N defect engineering and π-conjugation structure into g-C₃N₄. The photocatalytic hydrogen evolution rate of up to 1541.6 μmol g⁻¹ h⁻¹ is acquired over the optimum DCN350, which has 7.5-fold increase over primal g-C₃N₄ (205.9 μmol g⁻¹ h⁻¹). The experimental study and density functional theory (DFT) investigations confirm that DCN350 with N defects not only can shorten band gaps for expanding the light absorption range via optimizing the electronic band structure, but also act as active sites for facilitating hydrogen evolution reaction. Besides, the –C≡N as strong electron-withdrawing functional group can make the isolated valence electrons delocalized to drive the charge spatial separation. Therefore, the light absorption capacity and charge separation/transfer of g‐C₃N₄ can be flexibly mastered via changing calcination temperature of g-C₃N₄ and NaBH₄. Overall, this study provides an opportunity for having a deep understanding the role of structural defects on ameliorating the photocatalytic evolution hydrogen activity.

精确的分子可调策略被认为具有提高用于析氢的无金属光催化剂的光催化性能的巨大潜力，但仍然是一项艰巨的任务。我们在此介绍了将 N 缺陷工程和 π 共轭结构集成到 gC ₃ N _{4 中}的逻辑设计。优化的 DCN350 获得了高达 1541.6 μmol g ^-1  h ^-1 的光催化析氢速率，比原始 gC ₃ N ₄ (205.9 μmol g ^-1  h ^-1）。实验研究和密度泛函理论 (DFT) 研究证实，具有 N 缺陷的 DCN350 不仅可以通过优化电子能带结构来缩短带隙以扩大光吸收范围，而且还可以作为促进析氢反应的活性位点。此外，-C≡N作为强吸电子官能团可以使孤立的价电子离域以驱动电荷空间分离。因此，通过改变gC ₃ N ₄和NaBH _{4 的}煅烧温度，可以灵活地控制g-C ₃ N ₄ 的光吸收能力和电荷分离/转移。 总的来说，这项研究为深入了解结构缺陷在改善光催化析氢活性方面的作用提供了机会。