The reasonable design of g-C₃N₄(CN)-based homojunctions is a promising method to improve the photocatalytic performance. Controlling the interfacial charge-transport process is challenging. Herein, Ag and P-doped CN (ACN and PCN) were selectively synthesized. The band edges of CN move downward continuously with increasing Ag or P doping concentration. CN/4ACN (type-II), CN/8PCN (S-scheme) and 4ACN/8PCN (S-scheme) were formed by suitable energy level matching, and their charge transfer mechanisms were confirmed via VB-XPS, UPS and ESR analysis. In the presence of the hole sacrificant triethanolamine (TEOA), both CN/4ACN and 4ACN/8PCN exhibited better H₂ evolution reaction (HER) rate than CN/8PCN due to the improvement in conductivity caused by Ag doping. However, only CN/8PCN and 4ACN/8PCN exhibited HER coupled with tetracycline (TC) degradation performance owing to the high redox potential of the S-scheme. Benefiting from a good carrier transport property and high redox potential, 4ACN/8PCN exhibited the best HER rate (2305.6 μmol·g⁻¹·h⁻¹) with TEOA as the hole sacrificant, which was 11.7 times than that of pure CN, respectively, and achieved a high HER rate (117.8 μmol·g⁻¹·h⁻¹) coupled with simultaneous TC degradation. This study provides a basic understanding of CN homojunctions, which shows potential for expanded applications in photocatalytic H₂ evolution and pollutant degradation.

合理设计gC ₃ N ₄ (CN)基同质结是提高光催化性能的一种有前景的方法。控制界面电荷传输过程具有挑战性。在此，选择性合成了Ag和P掺杂CN（ACN和PCN）。随着Ag或P掺杂浓度的增加，CN的能带边缘不断向下移动。CN/4ACN (type-II)、CN/8PCN (S-scheme) 和 4ACN/8PCN (S-scheme) 通过适当的能级匹配形成，并通过 VB-XPS、UPS 和 ESR 分析证实了它们的电荷转移机制。在空穴牺牲剂三乙醇胺（TEOA）存在下，CN/4ACN和4ACN/8PCN均表现出更好的H ₂由于Ag掺杂提高了电导率，析出反应（HER）速率高于CN/8PCN。然而，由于S方案的高氧化还原电位，只有CN/8PCN和4ACN/8PCN表现出HER与四环素(TC)降解性能。得益于良好的载流子传输性能和高氧化还原电位，以TEOA为空穴牺牲剂时，4ACN/8PCN表现出最佳的HER速率（2305.6 μmol·g ^-1 ·h ^-1），分别是纯CN的11.7倍，并实现了高 HER 速率（117.8 μmol·g ^-1 ·h ^-1），同时 TC 降解。这项研究提供了对 CN 同质结的基本了解，显示了在光催化 H _{2中扩展应用的潜力}演化和污染物降解。