Zeolitic imidazolate frameworks derived novel polyhedral shaped hollow Co-B-O@Co₃O₄ electrocatalyst for oxygen evolution reaction

Abstract

The development of highly effective and low-cost non-noble metal electrochemical catalysts for oxygen evolution reactions (OER) is a major challenge for overall water splitting and rechargeable metal-air batteries. In this study, we develop a novel hollow cobalt-borate modified cobalt oxide composite (denoted by Co-B-O@Co₃O₄) catalyst derived from zeolitic imidazolate framework-67 (ZIF-67) for electrochemical OER. The Co-B-O@Co₃O₄ was easily synthesized via pyrolysis of ZIF-67 in Ar and air to produce hollow Co₃O₄ (denoted by h-Co₃O₄), followed by simple NaBH4 treatment at ambient temperature for 4 h. The unique polyhedral morphology was well preserved during the NaBH4 treatment. Benefiting from its structural and compositional merit, the as-synthesized Co-B-O@Co₃O₄ exhibit excellent electrocatalytic activity and long-term stability for OER. Also, we conducted the OER test using a Co-B-O@Co₃O₄ catalyst in a neutral pH environment for further investigation. Our study can provide an insight into catalyst modification step to enhance the overall performance while keeping its physical structure simultaneously. using metal-organic framework for the electrochemical catalyst thus can be recognized as a method for producing a highly active, long-term working and novel engineered electrocatalyst for OER applications.