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Nanoscale catalyst based on a heterometallic carboxylate complex of platinum and iron for hydrogen-air fuel cells
A nanoscale bimetallic alloy catalyst PtFe/C is prepared by pyrolysis of the heterometallic platinum-iron carboxylate complex [PtFe(OAc)4]2O⋅4CH2Cl2 on Vulcan XC-72 carbon black. It is characterized by X-ray powder diffraction analysis, X-ray fluorescence spectroscopy, transmission electron microscopy, and electrochemical methods. Its activity in the oxygen reduction reaction (ORR) is tested in an aqueous H2SO4 electrolyte in model conditions, using a rotating disc electrode (RDE) technique, and in the membrane electrode assembly of the hydrogen-air single fuel cell. The synthesized catalyst is a tetragonal PtFe intermetallic compound with Pt:Fe = 1:1 atomic ratio. It is uniformly distributed over the carbon support with a predominant metal particle size between 3 and 6 nm. The ORR specific activity of the prepared alloy catalyst is superior to that of a commercial Pt/C E-Tek catalyst and, thus, the PtFe/C catalyst may be a promising cathode material for hydrogen-air fuel cells.