Insight into enhanced Fenton-like degradation of antibiotics over CuFeO based nanocomposite: To improve the utilization efficiency of OH/O via minimizing its migration distance.

In Fenton or Fenton-like processes, the key step is to catalyze HO and produce highly reactive OH radicals. More efforts are then focus on designing efficient heterogeneous Fenton catalysts by activating HO to generate 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 OH utilization efficiency by regulating surface chemical reactions to minimizing its migration distance to the target pollutant. C doped g-CN incorporated CuFeO (CCN/CuFeO) exhibited almost ten times higher ofloxacin degradation rate constant than our previously reported CuFeO {012} catalyst (0.1634 vs 0.0179 min). Since similar amount of 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-CN and CuFeO established a closed-circuit surface Fenton reaction mechanism. HO was adsorbed and decomposed into OH/O over ≡Cu  site in CuFeO. The successful construction of CCN/CuFeO creates a negative surface potential and benefits the enrichment of target antibiotics from water, which greatly reduces the migration distance of OH/O to adjacent pollutant and then increases the OH/O utilization efficiency by avoiding the unwanted quenching. Hence, CCN/CuFeO possesses superior Fenton catalytic activity and long-term stability.