The enhanced P-nitrophenol degradation with Fe/Co3O4 mesoporous nanosheets via peroxymonosulfate activation and its mechanism insight

In current work, iron doping Co3O4 (Fe/Co3O4) mesoporous nanosheets with different iron ratios were successfully prepared to degrade P-nitrophenol (PNP) via peroxymonosulfate (PMS) activation. The obtained optimal 0.15Fe/Co3O4 exhibited the best PMS activation performance, almost 100% of PNP can be removed at pH = 5.5 in 60 min with negligible Co leaching. The excellent PMS activation performance of 0.15Fe/Co3O4 was mainly attributed to the enhanced electron transfer efficiency of Co2+/Co3+ and Fe2+/Fe3+ cycles and abundant oxygen vacancies, which benefiting in promoting more hydroxyl radical (•OH), sulfate radical (SO4•−), and singlet oxygen (1O2) generation. And the intimate relationship between PNP degradation efficiency and the contents of Co2+, Fe2+, Ovac in xFe/Co3O4 was obseved. Meanwhile, the mechanism for improved PMS activation efficiency was proposed based on ROSs quenching, XPS, and ESR results. In addition, the degradation pathway of PNP was explored based on the intermediates determined via the gas chromatography-mass spectrometer (GC-MS). This study can provide an effective strategy to obtain Co based catalysts with excellent PMS activation for recalcitrant pollutants degradation.