ABSTRACTIn this work the CSGP was applied for preparation of Pt-WOx and its coatings on carbon black, silver and titan substrates. Saturated tungsten sol (0.15M) was prepared by dissolving (NH4)4W5O17 2.5 H2O in ascorbic acid solution. To this solution H2PtCl6 was added to obtain the molar ratio Pt:W=l. 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 10–65μm) were very adherent. Ascorbate aqueous tungsten-platinum sol diluted to 0.03 or 0.06 M ΣMe 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.
Preparation of continuous alumina gel fibres by aqueous sol–gel process