Hollow NiCo₂O₄-ZnO-Co₃O₄-/N-C Micro-Cage for Synergistic Bisphenol A Degradation by Activating Persulfate

The NiCo2O4-ZnO-Co3O4-/N-C micro-cage was successfullysynthesizedby calcination of the precursor obtained from a hollow ZIF-8/ZIF-67with nickel nitrate. The preparation process concerning ion exchangeand leaching was illustrated by the investigation of the compositionand structure of the composites. As a catalyst for the activationof persulfate (PDS) to degrade bisphenol A (BPA), it was discoveredthat the BPA degradation in the presence of NiCo2O4-Co3O4-ZnO/N-Cwas more efficient than the solids obtained by ZIF-67 with nickelnitrate, indicated by the sevenfold increase of the apparent reactionrate. The further electrochemical analysis evidenced that the electrontransfer was more easily accomplished in the system of BPA-PDS-NiCo2O4-Co3O4-ZnO/N-C.This enhanced activity of NiCo2O4-Co3O4-ZnO/N-C was mainly due to thehollow structure, the synergistic effect of NiCo2O4, as well as the smaller size of the active species, whichfacilitated the transportation of molecules and ions as well as theactivation of PDS. TheNiCo(2)O(4)-ZnO-Co3O4-/N-C micro-cage was successfullysynthesized by calcination of the precursor obtained from a hollowZIF-8/ZIF-67 with nickel nitrate.