Ceria based supports are commonly used as supports for metal catalysts. Often, these supports are of interest because their redox properties enhance reactions that are commonly attributed to the metal particle. However, ceria-based catalysts also have activity for reactions that are typically metal catalyzed, for example the hydrogenation of acetylene. The present work demonstrates that the ability of ceria to activate hydrogen is enhanced in ceria-zirconia mixed metal oxide catalysts. H2/D2 isotopic exchange is used to provide a quantitative measure for this ability. Different types of active sites with different activation energies are identified for the exchange reaction using in-situ IR spectroscopy and kinetic studies. Detailed physico-chemical characterization is performed to obtain structure-property relationships, and a kinetic model is obtained. Most importantly, it is shown that the H2/D2 exchange activity increases with decreases crystallite size of ceria-zirconia. In addition, the presence of defect sites from surface reduction of ceria-zirconia has a strong impact on the H2/D2 exchange reaction. Correlations of H2/D2 exchange activity with catalytic performance in reactions for upgrading bio-oils will be discussed.

Hydrogen-deuterium exchange over ceria-zirconia catalysts

247th National Meeting (2014)

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