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Abstract: Pt45Ru45M10/C (M=Fe, Co, and Ni) catalysts were synthesized and physical and electrochemical properties were analyzed by XRD, TEM, CO stripping and methanol electro-oxidation activity measurement. Among these catalysts, the Pt45Ru45Fe10/C catalyst exhibited the highest mass activity of 2.6A/gcatal. while those of the Pt45Ru45Co10/C and Pt45Ru45Ni10/C catalysts were 2.2 and 2.5A/gcatal., respectively. In the case of specific activity, the catalysts exhibited much higher activities of 110 (130%), 120 (140%) and 150 (170%) mA/m2 for the Fe, Co and Ni incorporated catalysts, respectively, than 88mA/m2 of a commercial PtRu/C catalyst. [Copyright &y& Elsevier]

Abstract: A stability test on direct methanol fuel cells (DMFCs) was carried out at current densities of 100, 150, and 200mAcm−2. Each test lasted for 145h in the three cases. X-ray diffraction, energy dispersive spectroscopy, and scanning electron microscopy were used for analysis of the membrane electrode assemblies (MEAs). The maximum power densities were 93.9, 79.9, and 55.1% of the initial value after operation at 100, 150, and 200mAcm−2, respectively. A PtRu black catalyst with an original particle size of 3.3nm was used for the anode electrode. For the MEAs operated at 100, 150, and 200mAcm−2, the PtRu particle sizes increased from the original size to 3.4, 3.9, and 4.2nm, respectively, while a Pt black catalyst used for the cathode electrode did not change in size. Dissolution of the Ru was observed, and the ratio of (Pt:Ru) changed from (53:47) in the case of the fresh MEA, to (54:46), (56:44), and (73:27) for the MEAs after operation at 100, 150, and 200mAcm−2, respectively. The equivalent weight of the NafionTM membrane increased from a weight of 1264g for a fresh membrane, to a weight of 1322, 1500, and 1945g with the increases in operating current density to 100, 150, and 200mAcm−2, respectively. [Copyright &y& Elsevier]

Electro-catalysts omitting platinum are of interest to reduce the cost of fuel cells. The development of non-Pt alloys for this purpose would require a large number of experiments. Palladium-based bimetallic electro-catalysts using eight different metals were computationally evaluated for the oxygen reduction reaction (ORR) and were made and tested in acidic media using combinatorial methods. A Pd-Co alloy showed the closest oxygen adsorption energy to platinum in simple theoretical model calculations, suggesting the highest ORR activity. This prediction was confirmed experimentally, suggesting that the single parameter of oxygen adsorption energy can be a useful guide to developing non-Pt oxygen reduction catalysts in the future.