Preparation of Pt/WO{sub 3} powders and thin coatings on carbon black and metal supports by the complex sol-gel process (CSGP)
Direct Methanol Fuel Cells (DMFC) have been recognized as one of the most promising systems of energy sources for automotive area. Oxidation of methanol in these cells is catalyzed by Pt (often mixed with other metals or/and oxides, e.g., Ru, Au, Os, Ir, Pd, Sn, Pb, Bi, Cr, Cu, Fe and W) on carbon black support. The catalysts can be applied either to electrodes (generally Teflon bonding) or to membranes. In this work the CSGP was applied for preparation of Pt-WO{sub x} and its coatings on carbon black, silver and titanium substrates. Saturated tungsten sol (0.15M) was prepared by dissolving (NH{sub 4}){sub 4}W{sub 5}O{sub 17}2.5 H{sub 2}O in ascorbic acid solution. To this solution H{sub 2}PtCl{sub 6} was added to obtain the molar ratio Pt:W=1. After evaporation and heating at 700 C for 2h homogeneous yellow-green powders were obtained. Another part of this solution was diluted with ethanol and after ultrasonic mixing used for preparation of coatings on Ag and Ti substrates by the immersion technique. Gel layers were dried at 200 C for 20h and then calcined at 700 C for 2h. The resulting white colored layers (thickness 10--65{micro}m) were very adherent. Ascorbate aqueous tungsten-platinum sol diluted to 0.03 or 0.06 M {Sigma}Me was used for preparation of Pt-W (10 and 20%) catalyst by impregnation of carbon black Vulcan XC-72, followed by thermal treatment in air, argon and hydrogen atmospheres.
- Research Organization:
- Inst. of Nuclear Chemistry and Technology, Warsaw (PL)
- OSTI ID:
- 20019149
- Resource Relation:
- Conference: 1997 Materials Research Society Fall Meeting, Boston, MA (US), 12/01/1997--12/05/1997; Other Information: PBD: 1998; Related Information: In: Materials for electrochemical energy storage and conversion II -- Batteries, capacitors and fuel cells. Materials Research Society symposium proceedings, Volume 496, by Ginley, D.S.; Doughty, D.H.; Scrosati, B.; Takamura, T.; Zhang, Z.J. [eds.], 702 pages.
- Country of Publication:
- United States
- Language:
- English
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