186,840 research outputs found
SYNTHESIS AND CHARACTERIZATION OF PLATINUM RUTHENIUM BIMETALLIC NANOPARTICLES AS CATALYSTS FOR DIRECT METHANOL FUEL CELLS
No full textPt-Ru-Ir Nanoparticles Prepared by Vapor Deposition as a Very Efficient Anode Catalyst for Methanol Fuel Cells
No full textPreparation of Pt-Ru-Ir nanoparticle catalysts on carbon black by a novel vapour deposition method is reported. Particle size as assessed by TEM is c.a. 2.5 nm with narrow distribution. Moreover, they are homogeneously dispersed on the substrate. The electrocatalytic activity of the particles towards methanol electrooxidation was investigated by cyclic voltammetry, chronoamperometry at constant potential and adsorbed CO-stripping voltammetry. It was found that these catalysts possess outstanding activity for methanol electrooxidation. This is over one order of magnitude higher than in state of art catalysts. The novel catalysts have the potential to bear significant performance improvement of DMFCs
Impiego di macchine sincrone provviste di gabbia per l�avviamento asincrono in sistemi di generazione distribuita
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Nano-catalizzatori polimetallici per elettro-ossidazione di metanolo e relativo metodo di preparazione
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Novel Pt-Ru nanoparticles formed by vapour deposition as efficient electrocatalyst for methanol oxidation, Part II. Electrocatalytic activity
No full textThe methods developed and described in paper–part I are employed to prepare nanometer size Pt-Ru particles on a Vulcan XC72R substrate with controlled metal loading. Transmission Electron Microscopy (TEM) confirmed uniform particles size (average diameter 2nm) and homogeneous dispersion of the particles over the substrate. Energy Dispersive X-ray absorption (EDX) analysis confirmed the compositional homogeneity. The catalytic activity of these supported nanoparticles with regard to methanol electrooxidation is investigated using cyclic voltammetry (CV), chronoamperometry (CA) and CO-stripping voltammetry techniques at temperatures between 25°C and 60°C. Such investigation concerns supported catalysts prepared with c.a. 10 and 18 wt% overall metal loading (Pt + Ru) onto the Vulcan XC72R substrate. Comparative testing of our catalysts and a commercial Pt-Ru/Vulcan reveals markedly superior activity for our catalysts. In fact, we observe for the latter a five-fold increase of the oxidation current as compared to a commercial Pt-Ru/Vulcan with equal metal loading. One of the reasons for the greater activity is found to be the very high dispersion of the metals over the substrate, i.e. the large surface area of the active phase. Other reasons are plausibly ascribable to the varied Pt/Ru composition and/or reduced presence of contaminants at the catalyst surface
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