N-coordinated Co containing porous carbon as catalyst with improved dispersity and stability to activate peroxymonosulfate for degradation of organic pollutants

Abstract Co-based carbonaceous materials are among the most effective heterogeneous catalysts to activate peroxymonosulfate (PMS) for the degradation of organic pollutants in water. However, present examples normally suffer the aggregation of catalyst and/or the leakage of active Co species especially when the Co content is high, resulting in a loss of reactivity and potential environmental risk. In this study, we report the use of a mixture of Co phthalocyanine and melamine as precursor for the preparation of a carbonaceous catalyst with N-coordinated Co (Co-NG) for PMS activation. The presence of Co phthalocyanine in the precursor facilitates the uniform distribution of Co species in carbonaceous substrate with high Co content of 8.0 wt.%, thus exhibiting remarkable catalytic reactivity for the degradation of a variety of organic pollutants. More importantly, the strong coordination by N atoms significantly enhances the Co stability and reduces the Co leaching during cyclic use. Experiment results demonstrate that both sulfate radicals (SO4•−) and hydroxyl radicals (HO•) contribute to the pollutant degradation with SO4•− as the main reactive species. Other reaction parameters including solution pH, the presence of inorganic anions, and natural organic matters were also investigated and evaluated. We reckon this study provides new insights for the design of efficient Co-based carbonaceous catalysts with high Co stability for water treatment application.