Integrating bimetallic nanoclusters onto a porous g-C3N4 support for efficient degradation of metronidazole: Performance and mechanism study

Preparing catalysts for efficient degradation of antibiotics is an important and challenging objective across various fields, from water treatment to public health. In this study, we developed CoMnOx/g-C3N4 hybrid catalysts by integrating CoMnOx bimetallic oxides onto a 3D porous g-C3N4 support via activated peroxymonosulfate (PMS), which achieved high degradation efficiency for metronidazole (99.8 %), as well as pollutants such as methyl orange (99.4 %), ofloxacin (97.0 %), tetracycline (86.8 %), and oxytetracycline (84.7 %). The joint experimental and theoretical findings demonstrate that the CoMnOx nanoclusters integrated in the catalyst significantly enhance the adsorption and activation of PMS, thanks to the synergistic effects of the Co and Mn sites. Therefore, we propose a non-free radical catalytic mechanism that relies on 1O2 as the primary active species, where radicals such as SO4 center dot-, center dot OH, and O2 center dot- primarily contribute to the formation of 1O2. We suggest that our work provides a model for clarifying the critical roles played by cooperative bimetallic nanoclusters in PMS activation for efficient antibiotic degradation, and also paves the way for new opportunities in designing and controlling chemical compounds for water treatment.