ISSN:
1572-879X
Keywords:
microcalorimetry
;
IR
;
ruthenium
;
tin
;
copper
;
ethylene
;
CO
;
adsorption
;
DFT
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Microcalorimetric measurements of the adsorption of H2, CO and C2H4 were conducted on silica-supported Ru, Ru/Sn, Ru/Cu and Cu catalysts; infrared spectroscopic measurements were made of adsorbed CO and C2H4. The adsorption of C2H4 leads to formation of di-σ-adsorbed ethylene and ethylidyne species on Ru/SiO2 at 300 K, with an initial heat of 160 kJ/mol. Ethylene adsorption at 203 K leads to the formation of di-σ-adsorbed ethylene, ethylidyne species and weakly adsorbed π-bonded ethylene. The initial heats are 110, 95 and 75 kJ/mol on Ru/SiO2, 5Ru/Sn/SiO2 and Ru/Cu/SiO2, respectively. Lower heats of CO and C2H4 adsorption are measured on Ru/Cu/SiO2, primarily as a result of these adsorbates binding on both Cu and Ru. Quantum chemical calculations employing density functional theory were performed using (0001) slabs of Ru and Ru/Sn. The results of these calculations indicate that Sn weakens the interaction of π-bonded ethylene, di-σ-bonded ethylene and ethylidyne species with Ru by 41, 23 and 15 kJ/mol, respectively. This behavior is in contrast to the effect of adding Sn to Pt and Pd, for which Sn preferentially weakens the bonding of ethylidyne species to the surface.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1019047806971
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