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 rangeof the renewable energy technologies, such as fuel cells and metal-air batteries. Owing to thegentle 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 Ptbasedmaterials. Among them, the metallic organic framework (MOF) structures have absorbedmuch attention thanks to their supreme properties like porous architecture, high specific surfacearea and homogeneous distribution of active sites inside the structure.In this study a simple Zn/Fe bimetallic zeolitic-imidazolte frameworks (ZIF) carbonizationmethod is utilized to synthesize a Fe-N-C hybrid with hierarchical nitrogen-doped porouscarbons [1,2]. Since high temperature can enhance the degree of graphitization and also increasethe conductivity of catalysts to elevate ORR activity, porous carbon catalysts derived fromMOFs must undergo a high-temperature pyrolysis.Due to the synergetic effect of bimetal doping the ORR activities of bimetallic MOF-derivedporous carbon ca1talysts are often better than that of single Zn (or Co, Fe) containing MOFderivedones [3,4]. In order to investigate the electrochemical properties of the synthesizedcatalyst, cyclic voltammetry, linear sweep voltammetry and chronoamperometry techniques wereused. The results reveal that Fe doping during the ZIF-8 synthesis stage was vital to gain thematerials’ well-defined morphology, tunable size, and good particle dispersion. Furthermore, ahigh ORR activity of the as-prepared material in both acidic and alkaline media was observed.

کلیدواژه ها:

fuel cell ، metallic organic framework ، high dispersion ، oxygen reduction