Zhang Xiao, Zhang Menglin, Guo Zhiren, Li Xiang, Liu Ting, Li Jinying, Zhang Dongxiang, Xu Xiyan
School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 102488, People's Republic of China.
Aerospace Institute of Advanced Materials & Processing Technology, Beijing 100074, People's Republic of China.
Langmuir. 2025 Aug 19;41(32):21535-21552. doi: 10.1021/acs.langmuir.5c02317. Epub 2025 Aug 7.
The persistent contamination of aquatic environments by tetracycline (TC) necessitates advanced remediation strategies. Herein, a ternary Fe-O-P-co-modified graphitic carbon nitride (FOPCN) was synthesized via structural integration of Fe-N configurations with O/P dual doping for efficient TC degradation in a solar-driven photo-Fenton system. This study pioneers the synergistic coupling of Fe-N coordination and heteroatomic O/P substitution to optimize charge dynamics. Comprehensive characterization confirmed the formation of Fe-N active sites and aromatic structures incorporated with the aromatic group, which collectively enhanced visible-light absorption, suppressed electron-hole recombination, and facilitated charge carrier redistribution. The optimized FOPCN2 demonstrated exceptional photoelectric efficiency (3.7-fold higher photocurrent density than pristine g-CN) and achieved 98.9% TC removal within 40 min of irradiation with a kinetic constant of 0.113 min, outperforming conventional systems. Mechanistic studies revealed dual enhancement pathways: Fe-N sites promoted electron transfer and Fe(III)/Fe(II) cycling, while the O/P dual doping enabled electron delocalization for improved charge mobility. The system exhibited remarkable pH adaptability (3-7), robust resistance to inorganic anions, and universal degradation capability for mixed organic pollutants. Three TC degradation pathways were identified through intermediate analysis, with radical trapping and EPR verification confirming the dominant roles of OH, e, and O. This work provides critical insights into structure-activity relationships for carbon nitride modification, establishing a paradigm for designing multifunctional photocatalysts for antibiotic-contaminated wastewater remediation.
四环素（TC）对水生环境的持续污染需要先进的修复策略。在此，通过将Fe-N构型与O/P双掺杂进行结构整合，合成了一种三元Fe-O-P共改性的石墨相氮化碳（FOPCN），用于在太阳能驱动的光芬顿系统中高效降解TC。本研究开创了Fe-N配位与杂原子O/P取代的协同耦合，以优化电荷动力学。综合表征证实了Fe-N活性位点和与芳基结合的芳族结构的形成，这些共同增强了可见光吸收，抑制了电子-空穴复合，并促进了电荷载流子的重新分布。优化后的FOPCN2表现出优异的光电效率（光电流密度比原始g-CN高3.7倍），并在40分钟的辐照时间内实现了98.9%的TC去除，动力学常数为0.113 min，优于传统系统。机理研究揭示了双重增强途径：Fe-N位点促进电子转移和Fe(III)/Fe(II)循环，而O/P双掺杂使电子离域以提高电荷迁移率。该系统表现出显著的pH适应性（3-7），对无机阴离子具有强大的抗性，并且对混合有机污染物具有普遍的降解能力。通过中间产物分析确定了三种TC降解途径，自由基捕获和电子顺磁共振验证证实了·OH、e和O的主导作用。这项工作为氮化碳改性的构效关系提供了关键见解，为设计用于抗生素污染废水修复的多功能光催化剂建立了范例。
