Zeolitic imidazolate framework induced CoFe-PBA/Carbides hollow cube toward robust bi-functional electrochemical oxygen reaction

The incorporation of a multi-stage porous structure in the design of bifunctional electrocatalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is crucial for facilitating efficient material transport processes in zinc-air batteries (ZABs). In this work, a combination of zeolitic imidazolate framework-67 (ZIF-67) templates and acid etching techniques is employed to integrate the micropores of CoFe Prussian blue analogue (CoFe-PBA), mesopores formed by acid etching, and the macropores derived from ZIF-67 templates. This integration results in the formation of sc-PBA/Carbides@NC hollow nanobox catalysts with a multi-stage porous structure. This allows maximum exposure of active sites within the catalyst and significantly enhances material transport during electrochemical reactions. As a result, the ZAB assembled with sc-PBA/Carbides@NC catalyst shows a peak power density of 235 mW cm−2 and excellent stability, thus indicating promising prospects for practical applications.