ZIF-67 derived Co-N/C loaded graphite particles as three-dimensional electrodes to promote the efficient degradation of tetracycline in the electrocatalytic oxidation-peroxymonosulfate system: Synergistic effect of reactive oxygen species

Abstract

In this study, ZIF-GP is synthesized using ZIF-67 in situ loaded GP. Co-N/C-GP is synthesized as a three-dimensional particle electrode by pyrolysis of ZIF-GP in a nitrogen atmosphere. A 3D electrocatalytic synergistic system (EO-Co-N/C-GP-PMS) is developed in combination with electrochemical oxidation (EO) and peroxymonosulfate activation (PMS). Continuous and efficient degradation of tetracycline (TC) is achieved through advanced oxidation processes (AOPs). The synthesis of ZIF-GP gives three-dimensional particle electrodes a controllable shape. Co-N/C-GP derived from pyrolysis has excellent stability and electrochemical catalytic properties due to its metal core structure encased in surface carbon and nitrogen layer. It is noteworthy that two cobalt species, Co NPs (Co0) and Co-N (Co3+/Co2+ in the N coordination), are identified on Co-N/C-GP, which is essential for stimulating PMS to generate ROS. Furthermore, the synergistic system (EO-Co-N/C-GP-PMS) promotes the conversion of N-coordinated Co3+/Co2+, promotes cobalt cycling, and enables continuous use of 3D particle electrodes. Removal of pollutants is primarily achieved through the collaborative action of reactive oxygen species (ROS) in EO-Co-N/C-GP-PMS. ROS generation pathways are investigated. The superiority of collaborative systems is proved. It also provides a new perspective for combining different AOPs methods.