Co3O4 anchored in N, S heteroatom co-doped porous carbons for degradation of organic contaminant: role of pyridinic N-Co binding and high tolerance of chloride

In this work, Co3O4 embedded nitrogen and sulfur co-doped porous char (Co3O4@NSC) was prepared after one-pot pyrolysis of N, S in-rich rubber powder (RP) to determine the binding relationship between Co nanoparticles and multiple doped heteroatoms. Results indicated pyridinic N was more easily to coordinate with Co3O4 nanoparticles, forming the pyridinic N-Co binding in Co3O4@NSC, which was the dominant catalytic sites for peroxymonosulfate (PMS) activation. Paracetamol (PCM) degradation was greatly facilitated with Cl- surrounding in Co3O4@NSC/PMS system due to the formation of large amounts of HOCl generated from the direct reaction of Cl- with PMS. The Cl↓ serving as a precursor of HOCl by reacting with PMS can be further strengthened by pyridinic N-Co bindings in Co3O4@NSC than the NSC. As a result, the pyridinic Co-N sites not only acted as the essential catalytic sites for PMS activation, but also accelerated the formation of HOCl at high level of Cl-.