Mineralization of norfloxacin in a CoFe-LDH/CF cathode-based heterogeneous electro-fenton system: Preparation parameter optimization of the cathode and conversion mechanisms of H2O2 to •OH

This study demonstrates an efficient heterogeneous electro-Fenton system with a CoFe-layered double hydroxide/carbon felt (CoFe-LDH/CF) cathode for norfloxacin (NFXN) removal. Two-dimensional CoFe-LDH prepared at the optimal temperature of 90 degrees C could produce sufficient catalyst dosages and highly crystallized honeycomb hexagonal nanoplates, revealing extraordinary (at least 90%) mineralization of NFXN at all pH values after 480 min of treatment. The brilliant catalytic activity presented over similar to 97% for the mineralization of NFXN after 5 cycles experiments, indicating the good reusability of the prepared cathode. According to density functional theory (DFT) calculations, center dot OH could be generated easily since the lower energy barriers were achievable for intermediates absorbed on Co atoms rather than those absorbed on Fe atoms, demonstrating that the activity trend remained Co > Fe on CoFe-LDH. In addition, the mechanisms of H2O2 generation on practical CoFe-LDH/CF cathodes were explored. The CF in the CoFe-LDH/CF cathode is a highly active and stable 2-electron ORR catalyst for H2O2 production, which provides sufficient substrates for center dot OH generation. This study potentially provides new insight into exploring the nature of reactions in hetero-EF systems.

Automated summary

This study demonstrates an efficient heterogeneous electro-Fenton system with a CoFe-LDH/CF cathode for norfloxacin removal. The cathode exhibited high catalytic activity and reusability, with mineralization rates exceeding 90% for all pH values. Furthermore, density functional theory calculations showed that •OH generation was easily achievable on Co atoms, indicating the activity trend remained Co > Fe on CoFe-LDH.