An insight into the bridging role of Co3O4 in MOF-derived binary metal oxide modified sheet-like g-C3N4 for photo-assisted peroxymonosulfate activation

Abstract

The utilization of carbon nitride (g-C₃N₄) inevitably faces structural defects and inadequacy in photocatalytic performance. Recently, metal–organic framework (MOF) derivative doping has emerged as a way to functionally alter catalysts. Herein, we synthesize a MOF-derived binary metal oxide (ZnO/Co₃O₄/C)-modified sheet-like g-C₃N₄ (ZCC-SCN) catalyst via a hydrothermal process combined with a co-pyrolysis method and apply it in a photo-assisted peroxymonosulfate (PMS) activation system. The pyrolytic derivatization process endows ZCC-SCN with more porosity and larger surface area to favor the interfacial adsorption and reactivity of substrates. We validate a distinct ternary heterojunction composed of Co₃O₄–g-C₃N₄ and ZnO–Co₃O₄ in MOF derivatives. More notably, the enhanced Co^III/Co^II cycling further supports the bridging role of Co₃O₄ in the synergistic photo-assisted PMS activation system. Finally, SO₄˙⁻ coupled with the more generated ˙O₂⁻ dominates together to drive the rapid degradation of tetracycline hydrochloride. Our work provides a new perspective on the MOF derivative modification to carbon-based materials and is meaningful for the investigation of photo-assisted PMS activation.