Hierarchical multi-active component yolk-shell nanoreactors as highly active peroxymonosulfate activator for ciprofloxacin degradation

Hierarchical yolk-shell Co3O4-C@CoSiOx nanoreactor with multi-active component was synthesized. The degradation efficiencies of CIP reach up to ∼98.2% only in 17 min under the optimal conditions. The fundamental improvement in performance might be due to the synergistic effect of structure and components: (1) hierarchical structure with nanosheet walls and yolk-shell structure endowed the catalyst with high surface area (∼232.47 m2/g) and fully exposed active sites; (2) abundant highly active ≡Co-OH+ were formed on the surface of CoSiOx, which was the primary active species to active PMS; (3) a large amount of oxygen vacancies and nitrogen-doped carbon promoted the decomposition of PMS through a non-radical process. The results revealed both the radical (SO4∙-, ∙OH and O2∙-) and non-radical (1O2 and direct charge transfer) were the dominated mechanisms of CIP degradation, in which the 1O2 and SO4∙- mainly contributed to the degradation process. Our work highlights that multi-component catalysts derived from MOFs with special structure have broad application prospects in AOPs.