The efficient and visible-light-active graphitic carbon nitride (gC₃N₄) has attracted attention for green H₂ production from solar energy through water splitting. However, the photocatalyst suffers faster recombination of photogenerated electron-hole pairs and a low visible light absorption efficiency. In this work, the ternary Ag-grafted gC₃N₄-gC₃N₄ heterostructures were synthesized using thermal polycondensation of urea and thiourea, followed by photo-deposition of the silver from silver nitrate. The formation of S-scheme heterojunction was confirmed through XRD, VB XPS, UV-Vis, Mott-Schottky, EPR and PL analyses. The X-ray photoelectron spectroscopy revealed the presence of nitrogen vacancies with Ag grafting. The H₂ production rate was the highest at 10.1 mmol g^-1 h^-1 with 2.5Ag/gC₃N₄-gC₃N₄, which was 3 and 8 times higher than that over gC₃N₄-gC₃N₄ and gC₃N₄, respectively. The addition of Ag mainly contributed to enhance the photocatalytic activity of the heterojunction due to its dual-function. Firstly, silver is attributed to enhance the localized surface plasmon resonance, which broadened the visible light absorption and secondly, the abundant electron capture due to the high Schottky barrier. Moreover, the existence of nitrogen vacancies further improved the separation of charge carriers and helped in carrier transportation. This work provides a new S-scheme heterostructure strategy for the sustainable utilization of solar radiation in the production of H₂ from water splitting at higher rates.

高效且可见光活性的石墨碳氮化物（gC ₃ N ₄）引起了人们对通过水分解成太阳能产生绿色H _2的关注。然而，光催化剂遭受光生电子-空穴对的更快复合并且可见光吸收效率低。在这项工作中，三元Ag接枝的gC ₃ N ₄ -gC ₃ N ₄通过脲和硫脲的热缩聚，然后从硝酸银中光沉积银，合成了异质结构。通过XRD，VB XPS，UV-Vis，Mott-Schottky，EPR和PL分析确认了S型异质结的形成。X射线光电子能谱揭示了Ag接枝存在氮空位。为H ₂生产速率为最高为10.1毫摩尔克^-1 ħ ^-1与2.5Ag / GC ₃ Ñ ₄ -GC ₃ Ñ ₄，这是高3个8倍，超过GC ₃ Ñ ₄ -GC ₃ Ñ ₄和gC ₃ N ₄， 分别。Ag的添加由于其双重功能而主要有助于增强异质结的光催化活性。首先，银被认为可以增强局部表面等离子体激元共振，从而扩大了可见光吸收范围；其次，归因于高的肖特基势垒，大量的电子俘获。此外，氮空位的存在进一步改善了电荷载流子的分离并有助于载流子的运输。这项工作提供了一种新的S方案异质结构策略，用于以更高的速率分解水生产H _2时可持续利用太阳辐射。