Microcalorimetric studies of interactions of ethene, isobutene, and isobutane with silica-supported Pd, Pt, and PtSn.

 NatalSantiago M.A., Podkolzin S.G., Cortright R.D., Dumesic J.A.

 Catalysis Letters 45(3-4), 155-163 (1997)

Link to publication details on publisher's server

Abstract

     Microcalorimetric measurements were made of the interaction of hydrogen, ethene, isobutene and isobutane at 300 K with silica-supported Pt, Pd, and PtSn catalysts. The initial heats of hydrogen adsorption on silica-supported Pd and Pt are 104 and 95 kJ/mol, respectively. The presence of Sn decreases the saturation uptake of hydrogen on the PtSn sample. The initial heats of ethene interaction with Pd/silica and Pt/silica are 170 and 145 kJ/mol, respectively. The presence of Sn decreases the initial heat to 115 kJ/mol on the PtSn sample. The initial heats of isobutene interaction with silica-supported Pd and Pt are 160 and 190 kJ/mol, respectively. The presence of Sn decreases the initial heat to 125 kJ/mol on the PtSn sample. It appears that ethene and isobutene adsorb dissociatively on silica-supported Pd and Pt to form alkylidyne species at 300 K, with an average strength of carbon-metal bonds for these species near 230 kJ/mol. Ethene and isobutene adsorb on silica-supported PtSn to form di-sigma- and pi-bonded alkene species at 300 K, with an average strength of carbon-metal bonds for these species near 190 and 130 kJ/mol, respectively. Isobutane appears to adsorb dissociatively on a small number of sites on silica-supported Pd and Pt, and this dissociation is also inhibited by Sn on PtSn samples.

Author Keywords:

hydrogen, ethene, isobutene, isobutane, palladium, platinum, microcalorimetry, density-functional theory

KeyWords Plus:

Sn/Pt(111) Surface Alloys, Crystal-Surfaces, Bonded Ethylene, Pt(111), Adsorption, Decomposition, Desorption, Pt(110)-(1x2), Hydrocarbons, Coadsorption

Address:

Department of Chemical Engineering, University of Wisconsin, Madison, WI 53706, USA.

Publisher:

Baltzer Sci Publ BV, Amsterdam

IDS Number: XG386, ISSN: 1011-372X  

Animation of DFT calculations