Preferential site displacement of carbon monoxide by phosphine on Rh/Al sub 2 O sub 3 surfaces

Journal Article · Thu Oct 18 04:00:00 EDT 1990 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100384a060· OSTI ID:6052915

Lu, Guangquan; Darwell, J E; Crowell, J E ^[1]

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1. Univ. of California, San Diego, La Jolla (USA)

Transmission infrared spectroscopy is used to show that specific bonding sites of CO are preferentially displaced upon exposure of a CO-saturated Rh/Al{sub 2}O{sub 3} surface to PH{sub 3}. Carbon monoxide is bound in three primary adsorption states on Al{sub 2}O{sub 3} supported Rh, with bridged, atop, and gem-dicarbonyl bonding. At all adsorption temperatures studied (90-300 K), phosphine exposure readily leads to removal of CO bound in gem-dicarbonyl sites. The other states of CO are perturbed in their bonding with the surface, as evidenced by a red shift to lower frequencies in the CO stretching vibrations. At surface temperatures {ge} 300 K, CO adsorbed in bridged sites are also displaced by phosphine adsorption. Production of Rh(CO)PH{sub 3} is spectroscopically verified upon PH{sub 3} exposure of a Rh/Al{sub 2}O{sub 3} surface containing only the gem-dicarbonyl species. Similarities are found between the observed surface displacement reactions and phosphine substitution in metal carbonyl clusters.

• OSTI ID: 6052915
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 94:21; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

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ADSORPTION
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CHALCOGENIDES
COMPLEXES
DATA
EXPERIMENTAL DATA
INFORMATION
LOW TEMPERATURE
MEDIUM TEMPERATURE
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHOSPHINES
PHOSPHORUS COMPOUNDS
RHODIUM COMPLEXES
SORPTION
SURFACE PROPERTIES
TRANSITION ELEMENT COMPLEXES