Enhanced peroxymonosulfate-based Fenton-like degradation performance by confined radical activation path and non-radical activation path inside yolk@shell nanoreactor

In peroxymonosulfate (PMS)-based Fenton-like reaction, there were two pathways for PMS activation: radical path on transition metal surface and non-radical path on heteroatom-doped carbon surface. In this work, CoS2/nitrogen-atom doped carbon (NC)@SiO2 yolk@shell nanoreactor was designed, on CoS2/NC surface, these two paths performed parallelly inside the nanoreactor, leading to an accelerated tetracycline degradation rate. 90.9% of removal efficiency was realized within 15 min, much higher than the reference samples, and the advantages of yolk@shell nanoreactor were illustrated in detail. Moreover, benefiting from the SiO2 shell protection, the leached cobalt ion was only 0.27 mg/L, which was 1/20 of the reference CoS2/NC without SiO2 shell. During the mechanism study, the two activation paths were identified by electron paramagnetic resonance tests, radical trapping experiments and electrochemical tests, where the SO4•- and 1O2 were responsible for tetracycline (TC) degradation. This study provided a new strategy to simultaneously accelerate radical activation path and non-radical activation path by using the yolk@shell nanoreactor, and it might inspire other high efficient catalyst design for PMS-based Fenton-like reaction.