A NEW METHOD OF DIRECT SYNTHESIS OF BIMETALLIC PHASES - SILICA-SUPPORTED PD-CU CATALYSTS FROM MIXED ACETYLACETONATES

The direct synthesis on a silica support of well defined, crystalline, mixed Pd-Cu bis-acetylacetonates has been achieved and the structure of these new compounds was determined by powder X-ray diffraction. The se clusters have been deposited on a silica support and their thermal decomposition under helium was followed by in situ X-ray diffraction, thermo-gravimetry and mass spectroscopy. Microcrystalline metallic all oys with a narrow distribution of composition and particle size in the 2-4 nm range are obtained. Infrared experiments of CO chemisorption c onfirm the homogeneity of composition of the particles but conclude to a partial coverage of palladium by copper.