Iron tetrasulfophthalocyanine functionalized graphene nanosheets for oxygen reduction reaction in alkaline media

A Fe-based macromolecule composite was synthesized by functionalizing graphene nanosheets (GNs) with iron tetrasulfophthalocyanine (FeTSPc), a non-noble electrocatalyst for oxygen reduction reaction (ORR) in alkaline media in a simple and greener way. Utilizing GNs as a support can avoid FeTSPc being washed away from the electrode surface and catalyze ORR in alkaline media. The predominant properties of GNs not only make Fe center in the N4-ring protrude to serve as a catalyst, but also increase the active sites, resulting in excellent ORR catalytic activity in alkaline electrolytes. Conversely, by taking advantage of the excellent solubility of FeTSPc which helps to prevent the aggregation of GNs, the composite (demonstrated as GNs-FeTSPc) showed a long-term stability in alkaline aqueous solution and maintained the catalytic activity. Better yet, the composite GNs-FeTSPc is insensitive to CO due to the special structure of FeTSPc and can facilitate ORR with a direct four-electron process which was demonstrated by the rotating disc electrode (RDE) results. Clearly, our nanohybrid catalysts show great potential in the large-scale practical application of alkaline fuel cells (AFCs).