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In the present work, methanol oxidation reaction was investigated on Pt particles of various diameters on carbon-nanofibers and carbon-black supports with different surface-oxygen concentrations, aiming for a better understanding of the relationship between the catalyst properties and the electrochemical performance. The pre-synthesized Pt nanoparticles in ethylene glycol, prepared by the polyol method without using any capping agents, were deposited on different carbon supports. Removal of oxygen-groups from the carbon supports had profound positive effects on not only the Pt dispersion but also the specific activity. The edge structures on the stacked graphene sheets in the platelet carbon-nanofibers provided a strong interaction with the Pt particles, significantly reconstructing them in the process. Such reconstruction resulted in the formation of more plated Pt particles on the CNF than on the carbon-black and exposure of more Pt atoms with relatively high co-ordination numbers, and thereby higher specific activity. Owing to the combined advantages of optimum Pt particle diameter, an oxygen-free surface and the unique properties of CNFs, Pt supported on heat-treated CNFs exhibited a higher mass activity twice of that of its commercial counterpart.

The electrooxidation of methanol was studied at elevated temperature and pressure by cyclic voltammetry and constant potential experiments at real fuel cell electrocatalysts. Ruthenium core and platinum shell nanoparticles were synthesized by a sequential polyol route, and characterized electrochemically by CO stripping at room temperature to quickly confirm the structure of the synthesized core–shell structure as compared to pure commercial Pt/C and Pt–Ru/C alloy catalysts. A significant promotional effect of Pt decorated Ru cores in the methanol oxidation was found at elevated temperatures and rather high‐electrode potentials. A negative potential shift of the methanol oxidation peak is observed for the Ru@Pt/C core–shell catalyst at moderate temperatures, while a significant shift to positive potentials of the methanol oxidation peak occurs for Pt/C catalysts. The onset potential for methanol oxidation is lowered some 200 mV from room temperature and up to 120 °C for all electrocatalysts, indicating that it is the thermal activity of water adsorption that dictates the onset potential. Direct methanol fuel cell experiments showed only small performance differences between Ru@Pt/C and Pt/C anode electrocatalysts, suggesting the necessity of render possible the formation of surface oxygen species at lower electrode potentials.

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The paper reports synthesis and characterization of electrocatalyst composed of Ru nanoparticles (NPs). The catalysts were prepared by a polyol process and deposited on carbon (Vulcan XC72) support and employed PVP as a stabilizer. The as-prepared sample did not show any diffraction peaks, suggesting an amorphous structure, and was highly active for oxidation of CO. Heating of the catalyst in an inert atmosphere, however, resulted in the crystallization of the particles. The heat treatment resulted in significant drops in the electrocatalytic activity, tentatively ascribed to carbonaceous deposits at the catalyst surface. The results demonstrate that stabilisers such as PVP will not pose a significant hindrance for low-temperature electrochemical reactions at these catalysts.

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