Cobalt in ZIF-8-ZIF-67 as dual catalyst for ZnO–Co3O4/C formation and Bisphenol A degradation with persulfate

Abstract

Composited zeolitic imidazolate framework-8-67 (ZIF-8-ZIF-67 and ZIF-8/ZIF-67) solids were synthesized via two processes, which resulted in different cobalt content in the solids. The experimental results suggested that the cobalt content in the solids had a significant influence on the transformation from ZIF to the corresponded composited oxides and catalytic performances. It was revealed from the composition and structure analysis that the cage-like cobalt oxide-zinc oxide/carbon composite (Co3O4–ZnO/C) derived from the ZIF-8/ZIF-67 with 9 wt% of cobalt via a two-step synthesis displayed an efficient activation of persulfate to decompose the Bisphenol A (BPA) as well as a robust reusability compared with the solid obtained by one-step synthesized ZIF-8-ZIF-67 with a cobalt content of 0.8 wt%, which displayed no catalytic activity. It was proposed that the Co3O4–ZnO/C facilitated the electrons transfer in the reaction system and a possible radical oxidation process occurred. Thus, the present could provide new insight for the design of composited organic framework and their functional materials for catalytic applications.