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1

Oxidation of CO and Propane on Pt-Au/Al2O3 Catalysts

Ruszel M., Grzybowska-Świerkosz B., Karpiński Z., Juszczyk W.

Polish Journal of Chemistry

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2008

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Vol. 82, nr 10

1991-1997

EN

Alumina-supported bimetallic Pt-Au catalysts appeared to be superior to that containing Pt alone in oxidation of CO and propane. Such a catalytic behaviour in combination with previous physical characterization data suggests that Pt and Au remain intimately mixed in the form of Pt-Au bimetallic particles and that the presence of Au in these particles modifies the behaviour of Pt. Reasons for the occurrence of this synergistic effect are discussed.

2

Oxidative Dehydrogenation of Isobutane on VOx/Oxide Support Catalysts: Effect of the Potassium Additive

Samson K., Grzybowska-Świerkosz B.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 7

1345-1354

EN

Effect of the potassium additive on physicochemical and catalytic properties in oxidative dehydrogenation (ODH) of isobutane has been studied for a series of vanadia-based catalysts supported on different oxides (SiO2, Al2O3, TiO2, MgO). The catalysts (denoted as VS where S is a cation of a support), containing 1 or 1.5 monolayer (mnl) of V2O5 were prepared by impregnation method, characterized by BET, XPS, isopropanol decomposition (probe reaction for acido-basic properties) and tested in isobutane ODH in the temperature range 250-450_C. For all the catalysts the K additive decreased the acidity and increased the basicity, decreased the total acitivity, and increased (with the exception of VMg catalyst) the selectivity to isobutene. The increase in the selectivity was attributed to the decrease in acidity and increase in basicity of the catalysts. For VMg, different distribution of carbon oxides and different kinetic scheme were observed (dominance of CO2 formed by a consecutive path over CO formed by a parallel route) as compared with other catalysts (dominance of CO over CO2). These facts suggest, that the decrease in the selectivity to isobutene by the K additive observed for VMg catalyst is due to modification by K of other than acido-basic properties (most probably interaction of the catalysts with oxygen), which control the selectivity in this case.

3

Acido-Basic Properties of Selective Oxidation Catalysts-an Overview

Grzybowska-Świerkosz B.

Polish Journal of Chemistry

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2003

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Vol. 77 / nr 5

627-636

EN

Various aspects of acido-basic properties of transition metal oxides - catalysts for selective oxidation processes - are reviewed. The acido-basic properties of these catalysts may depend on coordination of the component ions, morphology of oxide crystals and the dispersion of an active oxide phase on a support. The methods for their determination are briefly described and the role of acido-basic properties in controlling the activity and selectivity of selective oxidation reactions is considered.