Preparation, Characterization And Electrocatalytic Performance Of Graphene-based Cathode Catalysts For Fuel Cells

Catalysts for the oxygen reduction reaction(ORR) are key components of fuel cells. Pt and its alloys remain the most efficient ORR catalysts. but the high cost and scarcity of Pt hamper further development of fuel cell technologies based on these materials. Therefore, Pt-free catalysts with high ORR activity, low cost and superior stability have been actively pursued. A variety of new types of graphene-based cathode catalyst for fuel cells have been produced in this paper and research their electrochemical properties and stability in detail. The research content includes the following two aspects:1. A conducting polymer polyaniline(PANI) is used to form a uniform coating layer over graphene oxide(GO) by liquid-liquid(L/L) interface polymerization method. Thermal annealing of the ferric salt and polyaniline-modified graphene oxide(FeCl3/PANI/GO) precursor in an inert environment leads to iron atoms and nitrogen atoms uniformly incorporation in the graphene frameworks, increasing the density of active sites on the catalyst. And finally obtained Fe and N-doped graphene nanocomposite(Fe-N-RGO). Electrochemical results revealed that the Fe-N-RGO shows high catalytic activity, less sensitivity for methanol cross-over and excellent stability for ORR.2. We describe a solvothermal method to in situ prepare N-doped graphene supported Co Fe2O4 nanoparticles hybrid materials as ORR catalyst. The Co Fe2O4 nanoparticles direct nucleation, growth, and anchoring on graphene oxide(GO) sheets with simultaneous nitrogen atoms incorporation in the graphene frameworks during the solvothermal treatment. Obtained a uniform CoFe2O4 nanoparticles over N-doped graphene. Due to the covalent coupling and synergetic effects of the Co Fe2O4 nanoparticles with N-doped graphene. Electrochemical results revealed that the Co Fe2O4/NGs hybrid materials shows greatly enhanced catalytic activity and excellent stability towards ORR in alkaline solution.