Achieving efficient and stable solar-to-hydrogen conversion is of great significance to the sustainable development of global energy. Herein, we report a novel strategy for metal functionalization via in-situ construction of metal coordination sites in graphitic carbon nitride (CN), in which pyrimidinone derivative ligands are incorporated onto CN framework through one-step vapor diffusion process, and then transition metal ions (such as Ni, Cu, Co) are covalently immobilized by strong coordination interaction. The coordination-introduced metal ions not only serve as catalytic reaction sites, but also improve the utilization of visible light through the metal ion to ligand charge transfer (MLCT) mechanism. Specially, the strong interaction between metal ion and ligand promotes charge separation by expanding the π-conjugated delocalization system of CN, which makes it possible to continuously generate hydrogen without noble metals. The optimal sample Ni/DBM(0.12%)-CN shows a hydrogen evolution rate of 68.6 μmol h⁻¹ (λ ≥ 420 nm) and a remarkable quantum conversion efficiency of 5.57% under irradiation of the light with wavelength of 450 nm. The mechanism of high-activity hydrogen production was studied through both experiments and theoretical calculations. This study provides a new strategy for designing cost-effective CN photocatalyst with alternative metal coordination sites for efficient visible light utilization.

实现高效稳定的太阳能到氢的转换对全球能源的可持续发展具有重要意义。在此，我们报告了一种通过原位进行金属功能化的新策略在石墨氮化碳 (CN) 中构建金属配位位点，其中嘧啶酮衍生物配体通过一步气相扩散过程结合到 CN 骨架上，然后过渡金属离子 (如 Ni、Cu、Co) 被强共价固定协调互动。配位引入的金属离子不仅可以作为催化反应位点，还可以通过金属离子到配体电荷转移（MLCT）机制提高可见光的利用率。特别是金属离子与配体之间的强相互作用通过扩展CN的π共轭离域体系促进电荷分离，这使得在没有贵金属的情况下连续产生氢成为可能。最佳样品 Ni/DBM(0.12%)-CN 的析氢速率为 68.6 μmol h ^-1( λ  ≥ 420 nm)，在波长为 450 nm 的光照射下，量子转换效率高达 5.57%。通过实验和理论计算研究了高活性制氢的机理。该研究为设计具有替代金属配位位点的具有成本效益的 CN 光催化剂提供了一种新策略，以实现有效的可见光利用。