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 successfully synthesized by calcination of the precursor obtained from a hollow ZIF-8/ZIF-67 with nickel nitrate. The preparation process concerning ion exchange and leaching was illustrated by the investigation of the composition and structure of the composites. As a catalyst for the activation of persulfate (PDS) to degrade bisphenol A (BPA), it was discovered that the BPA degradation in the presence of NiCo2O4-Co3O4-ZnO/N-C was more efficient than the solids obtained by ZIF-67 with nickel nitrate, indicated by the sevenfold increase of the apparent reaction rate. The further electrochemical analysis evidenced that the electron transfer 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 the hollow structure, the synergistic effect of NiCo2O4, as well as the smaller size of the active species, which facilitated the transportation of molecules and ions as well as the activation of PDS.