Initiating nonradical-dominated persulfate activation by N doping on Co3O4 enables efficient organic pollutant degradation

Abstract

Low-cost and efficient catalysts are decisive for the broadened implementation of advanced oxidation processes (AOPs) in wastewater remediation. Based on the modified hypothesis by inducing a nonradical pathway, we designed the N-doped Co3O4 (N-Co3O4) for peroxydisulfate (PDS) activation by facile post-treatment of Co3O4 with N precursor at low temperature. The N-Co3O4/PDS system exhibited excellent degradation efficiency (98.7 %) in 1 h for the removal of typical organic pollutant (acid organic 7), enhanced by 41.4 % compared to Co3O4/PDS. Remarkably, distinguish from sluggish degradation by Co3O4, N-Co3O4 achieved an enhanced kinetic process with the degradation efficiency of 97.7 % in 5 min, making it outstanding to save time and economic costs. We discovered the activation mechanism by N-Co3O4 covered the nonradical pathways of singlet oxygen (1O2) and electron transfer, overcoming the sole radical pathway of Co3O4. The emerging oxygen vacancies on N-Co3O4 boosted the generation of active 1O2 with •O2− intermediates, and benefited the electron transfer process with lower resistance. N doping introduced Co-N basic sites facilitated the PDS adsorption, improving the electron transfer capability. This study proposes a facile protocol to convert transition metal oxide to functional catalyst and demonstrates the immense potential to create nonradical dominated degradation.