Sustainable Fe and Cu Sites Double Redox Cycle Boosting Fenton-like Degradation of Organic Pollutants

• Published in: Environmental science & technology Vol. 59; no. 31; pp. 16812 - 16821
• Main Authors: Hu, Yi, Zhou, Yao, Ding, Rongjian, Ye, Xinchun, Chu, Chu, Liu, Ling-Ling, Tian, Lei, Jiang, Xunheng, Zhang, Long-Shuai, Zou, Jian-Ping, Luo, Shenglian
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 12.08.2025
• Subjects: Carbon nitride; Catalysis; Catalysts; Continuous flow; Copper; Copper - chemistry; Degradation; Density functional theory; Electronic structure; Energy of dissociation; Free energy; Heat of formation; Hydrogen peroxide; Hydrogen Peroxide - chemistry; Iron; Iron - chemistry; Oxidation-Reduction; Physico-Chemical Treatment and Resource Recovery; Pollutants; Single atom catalysts; Stability; Sulfamethoxazole; Synergistic effect; Wastewater treatment; Water Pollutants, Chemical; Water pollution; Fenton-like; Fe−Cu dual-sites; pollutant degradation; dual-atom catalysis; double redox cycle
• ISSN: 0013-936X; 1520-5851; 1520-5851
• DOI: 10.1021/acs.est.5c07284

Single-atom catalysts (SACs) show excellent activity and selectivity in Fenton-like reactions due to the atomically dispersed and homogeneous active sites. However, the sluggish redox kinetics of single-atom sites cause poor stability and durability. Herein, a graphitic carbon nitride-supported Fe and Cu dual-site catalyst with N4–Fe–Cu-N3 configuration (FeCu-CN) was designed and prepared, which promotes H2O2 activity through a sustainable dual-metal redox cycle and shows excellent pollutant degradation performance. The optimized FeCu-CN efficiently activates H2O2 to degrade sulfamethoxazole, with 23 and 4 times higher rates than Fe-CN and Cu-CN, respectively. Experimental and density functional theory (DFT) calculations indicate that the Cu site of FeCu-CN optimizes the electronic structure of Fe site and provides electrons to facilitate the Fe­(III)/Fe­(II) cycle. The reduction of Cu­(II) by H2O2 and •O2 – could promote the Cu­(II)/Cu­(I) cycle, maintaining the catalytic activation stability of FeCu-CN. Moreover, the synergistic effect of Fe and Cu sites in FeCu-CN promotes the adsorption of H2O2 and reduces the dissociation energy barrier of H2O2. The FeCu/H2O2 system exhibits strong resilience to changes in pH (from 3.18 to 9.35) and the coexisting substances. In continuous flow experiments, it also shows a long-term degradation effect on water pollutants. The FeCu-CN/H2O2 system has excellent anti-interference ability and application potential. This study develops a strategy for a persistent dual-metal synergistic redox cycle, providing new mechanistic insights for designing Fenton-like catalysts in efficient and environmentally friendly wastewater treatment.