Investigation of ZIF-derived Fe-N co-doped Carbon in Metal− Organic Frameworks

Electrochemical oxygen reduction reaction (ORR) is of great significance in an extensive range of the renewable energy technologies, such as fuel cells and metal-air batteries. Owing to the gentle reaction kinetics, Pt-based materials are currently the state-of-the-art catalysts. However, because of high cost and lack of Pt sources, a lot of alternatives have been proposed to the Ptbased materials. Among them, the metallic organic framework (MOF) structures have absorbed much attention thanks to their supreme properties like porous architecture, high specific surface area and homogeneous distribution of active sites inside the structure. In this study a simple Zn/Fe bimetallic zeolitic-imidazolte frameworks (ZIF) carbonization method is utilized to synthesize a Fe-N-C hybrid with hierarchical nitrogen-doped porous carbons [1,2]. Since high temperature can enhance the degree of graphitization and also increase the conductivity of catalysts to elevate ORR activity, porous carbon catalysts derived from MOFs must undergo a high-temperature pyrolysis. Due to the synergetic effect of bimetal doping the ORR activities of bimetallic MOF-derived porous carbon ca1talysts are often better than that of single Zn (or Co, Fe) containing MOFderived ones [3,4]. In order to investigate the electrochemical properties of the synthesized catalyst, cyclic voltammetry, linear sweep voltammetry and chronoamperometry techniques were used. The results reveal that Fe doping during the ZIF-8 synthesis stage was vital to gain the materials’ well-defined morphology, tunable size, and good particle dispersion. Furthermore, a high ORR activity of the as-prepared material in both acidic and alkaline media was observed.