Iron- and Nitrogen-Doped Graphene-Based Catalysts for Fuel Cell Applications

Abstract

A simple synthesis method was used to prepare an active oxygen reduction reaction (ORR) electrocatalyst based on iron and nitrogen co-doped graphene for polymer electrolyte fuel cell applications. For the synthesis of the ORR catalysts, two different graphene-based materials, commercially available graphene (Gra) and graphene oxide (GO), were used as the carbon substrates. The half-cell experiments conducted by using the rotating disc electrode (RDE) method revealed that Fe−N−Gra showed much higher ORR electrocatalytic activity than Fe−N−GO in alkaline medium. This is attributed to the higher surface area, micro-/mesoporous nature and larger amount of Fe-Nx/amine moieties present in Fe−N−Gra compared to Fe−N−GO, as shown by different physicochemical methods. Almost half of the iron was confirmed to be in highly active Fe-Nx form by 57Fe Mössbauer spectroscopy. Thus, the Fe−N−Gra as ORR catalyst was further selected to apply this for both proton exchange membrane (PEM) and anion exchange membrane (AEM) fuel cell tests.