Enhancing the Fenton-like reactions performance of copper-iron oxide by inducing a lower valence state using oxidized g-C3N4 support

Copper and iron metal oxides are frequently utilized as Fenton-like catalysts, promoting H2O2 decomposition to produce •OH. However, synthesizing bimetallic copper-iron catalysts often requires a significant pH difference, resulting in uneven dispersion of the metals on the microscopic scale, limiting their synergistic effect. In this study, highly dispersed bimetallic copper-iron catalysts were constructed by adding a ligand to simultaneously precipitate Fe3+ and Cu2+ during the hydrothermal process. In addition, the dispersion of the active catalytic components was enhanced by oxidizing g-C3N4 as support, which significantly improved the Fenton-like activity. The surface electron transfer of oxidized g-C3N4 and the bimetallic copper-iron catalyst, as well as the synergistic effect between copper and iron, promoted the cycling of Cu2+/Cu+ and Fe3+/Fe2+, which could degrade 99.4% of 500 mg/L of rhodamine B within 90 min. Characterization techniques (XRD, BET, SEM, XPS, Zeta potential) confirm the advantages: large specific surface area, high dispersibility, and the presence of low-valence metals. Free radical quenching experiments and EPR characterization demonstrated that •OH and 1O2 were the primary reactive oxidation species. The degradation of rhodamine B by Cu2Fe@OCN in fixed-bed experiments showed remarkable stability and reactivity.