Insight into enhanced Fenton-like degradation of antibiotics over CuFeO2 based nanocomposite: To improve the utilization efficiency of 2.3•OH/O2•-via minimizing its migration distance

In Fenton or Fenton-like processes, the key step is to catalyze H2O2 and produce highly reactive center dot OH radicals. More efforts are then focus on designing efficient heterogeneous Fenton catalysts by activating H2O2 to generate center dot OH at the highest possible steady state concentration. In this study, using the antibiotic ofloxacin as target organic pollutant, we firstly demonstrate a point of view for improving center dot OH utilization efficiency by regulating surface chemical reactions to minimizing its migration distance to the target pollutant. C doped g-C3N4 incorporated CuFeO2 (CCN/CuFeO2) exhibited almost ten times higher ofloxacin degradation rate constant than our previously reported CuFeO2 {012} catalyst (0.1634 vs 0.0179 min-1). Since similar amount of center dot OH was generated, the different inhibition effect of tert-butyl alcohol and nitrobenzene on the ofloxacin degradation confirmed that the much-enhanced ofloxacin degradation was attributed to the surface Fenton reaction process. According to XPS and EXAFS characterization, the C-O-Cu bond between g-C3N4 and CuFeO2 established a closed-circuit surface Fenton reaction mechanism. H2O2 was adsorbed and decomposed into center dot OH/O2 center dot- over equivalent to Cu + site in CuFeO2. The successful construction of CCN/CuFeO2 creates a negative surface potential and benefits the enrichment of target antibiotics from water, which greatly reduces the migration distance of center dot OH/O2 center dot-to adjacent pollutant and then increases the center dot OH/O2 center dot- utilization efficiency by avoiding the unwanted quenching. Hence, CCN/CuFeO2 possesses superior Fenton catalytic activity and long-term stability.

Automated summary

This study demonstrates that regulating surface chemical reactions to minimize migration distance can improve the utilization efficiency of ·OH radicals. The CCN/CuFeO2 catalyst showed superior Fenton catalytic activity and stability in the degradation of ofloxacin, with a ten times higher degradation rate constant compared to the previously reported CuFeO2 catalyst.