Silica palladized

Table V. Oxidizing Properties of Pure and Palladized Silica-Alumina...

Palladium-silica catalysts prepared from tetra-ammine palladous nitrate (to avoid chlorine introduction) showed a marked reduction effect , viz, the specific activity for benzene hydrogenation decreased with increased reduction temperature, i.e., 573 or 723Various explanations were considered, including a metal-support interaction. After reduction at 873 K, X-ray diffraction provided clear evidence of chemical reaction and at lower temperatures silicon insertion into palladium might still occur, which could either disrupt the palladium ensembles required for benzene adsorption or modify the properties of single palladium atoms, if these are the active sites. 

In this case also, charcoal was the only successful catalyst under the moderate conditions of temperature used. Negative results were obtained with platinized asbestos, palladized asbestos, nickel (supported on silica... 

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