Supported metal catalysts are of considerable importance because of a multitude of applications, as e. g. the production of liquid hydrocarbon fuels. We employed XAFS spectroscopy to follow ethylene hydrogenation over Pt and Pd nanoparticle catalysts supported on porous SiO2 at room temperature. In these studies, performed in operando, by monitoring the reaction product with mass spectroscopy while measuring XAFS data, we investigated the effects of ethylene to hydrogen ratio (varied from 0 to 100%) on the catalytic activity and structure of the particles. For each catalyst we observed a pronounced transition in structural and electronic properties at a gas ratio of ~50%. While the nature of structural transformations was different for both catalysts, they did not affect their catalytic activity which changed gradually with the gas concentration across the transition ratio. Cumulatively, these results indicate that the restructuring resulted from the dehydrogenation of the catalysts, and the resultant hydrogen evolution compensated for the non-stoichiometric ethylene to hydrogen ratio above the transition.

In operando XAFS spectroscopy study of the ethylene hydrogenation by nanoparticle catalysts

246th National Meeting (2013)

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