Synergy between F-doped g-C3N4 and manganese cobalt oxides (MnxCo3−xO4) mediated peroxymonosulfate activation for efficient degradation of emerging pollutants

The rapid redox cycle of metal active sites and effective surface reactions are crucial factors to activate peroxymonosulfate (PMS) for environmental remediation. Herein, a novel F-g-C3N4/MnxCo3−xO4 composite as high-efficient PMS activator was successfully constructed by a one-step hydrothermal method for the degradation of 1,1-diamino-2,2-dinitroethylene (FOX-7). It was discovered that F doping could narrow the band gap, and enhance the light absorption range and the separation of photogenerated electron-hole pairs. Among all samples, the catalytic activity of F-CN/MCO was higher than that of MCO and CN/MCO. This can be attributed to the unique materials morphology and the synergistic effect of photocatalytic and chemical catalytic driven PMS activation. Quenching experiments and electron paramagnetic resonance (EPR) proved that both radical and non-radical pathways are responsible for the degradation of FOX-7, and singlet oxygen (1O2) was identified as the predominant active species. Importantly, the synergy between Co2+/Co3+ and Mn2+/Mn3+ couples enhanced more electron transfer and better redox potential, thus greatly promoting the photocatalytic activation of PMS. This work provides a novel approach for designing efficient catalyst to promote the redox behavior of metal species in sulfate radical-based advanced oxidation processes.