For the purpose of improving the photocatalytic performance of graphitic carbon nitride (g-C₃N₄) in the field of contaminant elimination, an in-situ malonamide-assisted strategy is provided to prepare carbon self-doping and structural defect co-modified g-C₃N₄ (CDCN) via preprocessing of the mixture of urea and malonamide followed by thermal copolymerization. Changing the initial malonamide dosage can precisely adjust the carbon doping level and structural defect concentration of CDCN. The characteristic results confirm that the doped C derived from malonamide was successfully implanted into the g-C₃N₄ framework by replacing sp² hybrid N atoms (C−N=C) in the heptazine units, simultaneously forming some structural defects. Additionally, the preprocessing endows CDCN with good textural properties. So, the optimal CDCN₂₀ shows remarkably enhanced visible-light photocatalytic activity in eliminating acetaminophen (APAP) and methylparaben (MPB) in water than pristine g-C₃N₄. By combining experimental and theoretical calculating results, the synergistic effect of C self-doping and structural defect promoting the photocatalytic performance of g-C₃N₄ is revealed thoroughly. This work provides a controllable strategy for synthesizing effective C self-doped g-C₃N₄ and a new insight into electronic structure and band structure-regulated photocatalytic oxidation mechanisms.

为提高石墨碳氮化物(gC ₃ N ₄ )在污染物消除领域的光催化性能，提供了原位丙二酰胺辅助策略制备碳自掺杂和结构缺陷共修饰的gC ₃ N ₄ (CDCN) 通过对尿素和丙二酰胺的混合物进行预处理，然后进行热共聚。改变初始丙二酰胺用量可以精确调节CDCN的碳掺杂水平和结构缺陷浓度。特征结果证实，来自丙二酰胺的掺杂 C通过取代 sp ^{2成功地植入到 gC} ₃ N _4骨架中庚嗪单元中的杂化N原子（C−N=C），同时形成一些结构缺陷。此外，预处理赋予 CDCN 良好的纹理特性。_{因此，与原始 gC 3} N ₄相比，最佳 CDCN ₂₀在消除水中的对乙酰氨基酚 (APAP) 和对羟基苯甲酸甲酯 (MPB) 方面显示出显着增强的可见光光催化活性。通过结合实验和理论计算结果，彻底揭示了C自掺杂和结构缺陷对促进gC ₃ N _{4光催化性能的协同作用。}该工作为合成有效的C自掺杂gC ₃ N _{4提供了一种可控策略}以及对电子结构和能带结构调节的光催化氧化机制的新见解。