Insight into the degradation of tetracycline hydrochloride by non-radical-dominated peroxymonosulfate activation with hollow shell-core Co@NC: Role of cobalt species

•Hollow shell-core Co@NC with exposed two different cobalt species (i.e., Co NPs and Co-Nx site) was prepared by on-step thermal conversion of ZIF-8@ZIF-67 precursor.•Cobalt species of Co@NC play a crucial role in the non-radical-dominated PMS activation and TCH degradation.•Co-Nx site could directly adsorb PMS (*PMS) and facilitate PMS decomposition to form 1O2 while Co NPs indirectly accelerate the generation of 1O2 via electron transfer.•Good stability and reusability, high environmental robustness and universal adaptability were demonstrated in Co@NC/PMS system.