| Abstract
| - Nanostructured PtRu/C catalysts have been prepared from a water-in-oil pseudomicroemulsion with the aqueousphase of a mixed concentrated solution of H2PtCl6, RuCl3, and carbon powder, oil phase of cyclohexane,ionic surfactant of sodium dodecylbenzene sulfonate (C18H29NaO3S), and cosurfactant n-butanol (C4H10O).Two different composing PtRu/C nanocatalysts (catalyst 1, Pt 20 wt %, Ru 15 wt %; catalyst 2, Pt 20 wt %,Ru 10 wt %) were synthesized. The catalysts were characterized by transmission electron microscopy, X-raydiffractometry, X-ray photoelectron spectroscopy, and thermogravimetric analysis, and the particles werefound to be nanosized (2−4 nm) and inherit the Pt face-centered cubic structure with Pt and Ru mainly in thezero valance oxidation state. The ruthenium oxide and hydrous ruthenium oxide (RuOxHy) were also foundin these catalysts. The cyclic voltammograms (CVs) and chronoamperometries for methanol oxidation onthese catalysts showed that catalyst 1 with a higher Ru content (15 wt %) has a higher and more durableelectrocatalytic activity to methanol oxidation than catalyst 2 with low Ru content (10 wt %). The CV resultsfor catalysts 1 and 2 strongly support the bifunctional mechanism of PtRu/C catalysts for methanol oxidation.The data from direct methanol single cells using these two PtRu/C as anode catalysts show the cell withcatalyst 1 has higher open circuit voltage (OCV = 0.75 V) and maximal power density (78 mW/cm2) thanthat with catalyst 2 (OCV = 0.70 V, Pmax = 56 mW/cm2) at 80 °C.
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