Metal-based catalyst could be used for efficient peroxymonosulfate (PMS) activation, but inevitably suffered from metal ion leaching. Metal-free graphitic carbon nitride (g-C3N4) materials that can activate PMS are more conducive for practical water treatment. In this study, g-C3N4 with both N-defects and P-doping (CN-NP) was synthesized, which mainly produce singlet oxygen (1O2), and 97 % of 4-CP (4-Chlorophenol) was removed by CN-NP/PMS/Vis reaction system within 60 min. The active species was identified by quenching experiments and electron spin resonance (ESR) tests, and the origin of mainly active species was further verified by the concentration change of PMS during the reaction. It was verified by experiments and theoretical calculations that the introduction of N-defects led to the separation of photoinduced electron-hole pairs and improved photocatalytic activity. Notably, density functional theory (DFT) revealed that both N-defects and P-doping are electron-deficient sites, and P-doping acts as the main PMS adsorption site to promote the loss of electrons from PMS to generate 1O2. In addition, the catalysts developed in this research were anticipated to be applied in real wastewater treatment, contributing to further comprehend the mechanisms of element doping and defect modification in g-C3N4 activating PMS, and providing new insights for the design of PMS-activating catalysts.

中文翻译：

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N 缺陷和 P 掺杂协同促进过氧单硫酸盐的氮化碳光催化活化：触发 1O2 的选择性生成以降解 4-氯苯酚


金属基催化剂可用于高效的过氧一硫酸盐 （PMS） 活化，但不可避免地会受到金属离子浸出的影响。可以激活 PMS 的无金属石墨氮化碳 （g-C3N4） 材料更有利于实际水处理。本研究合成了同时具有 N 缺陷和 P 掺杂 （CN-NP） 的 g-C3N4，主要产生单线态氧 （1O2），并在 60 分钟内通过 CN-NP/PMS/Vis 反应体系去除了 97% 的 4-CP（4-氯苯酚）。通过淬灭实验和电子自旋共振 （ESR） 测试鉴定出活性物质，并通过反应过程中 PMS 的浓度变化进一步验证了主要活性物质的来源。实验和理论计算验证了 N 缺陷的引入导致光诱导电子-空穴对分离，提高了光催化活性。值得注意的是，密度泛函理论 （DFT） 揭示了 N 缺陷和 P 掺杂都是缺电子位点，P 掺杂作为 PMS 的主要吸附位点，促进 PMS 的电子损失产生 1O2。此外，本研究开发的催化剂有望应用于实际废水处理，有助于进一步理解 g-C3N4 活化 PMS 中元素掺杂和缺陷修饰的机制，并为 PMS 活化催化剂的设计提供新的见解。