Adsorption of carbon monoxide on manganese-promoted rhodium/silica catalysts as studied by infrared spectroscopy

• Published in: Journal of physical chemistry (1952) Vol. 94; no. 4; pp. 1576 - 1581
• Main Authors: Stevenson, S. A, Lisitsyn, A, Knoezinger, H
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 01.02.1990
• Subjects: ADSORPTION; BIMETALS; CALCULATION METHODS; CARBON COMPOUNDS; CARBON MONOXIDE; CARBON OXIDES; CATALYSTS; CHALCOGENIDES; DATA; DATA ANALYSIS; ELEMENTS; EXPERIMENTAL DATA; INFORMATION; INFRARED SPECTRA; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; MANGANESE; MEASURING INSTRUMENTS; MEASURING METHODS; METALS; MINERALS; NUMERICAL DATA; OXIDE MINERALS; OXIDES; OXYGEN COMPOUNDS; PLATINUM METALS; RHODIUM; SILICA; SILICON COMPOUNDS; SILICON OXIDES; SORPTION; SPECTRA; TRANSITION ELEMENTS 400201 > Chemical & Physicochemical Properties
• ISSN: 0022-3654; 1541-5740
• DOI: 10.1021/j100367a066

Infrared spectroscopy was used to study the adsorption of carbon monoxide on silica-supported rhodium catalysts promoted with manganese oxide. Addition of the promoter suppressed overall adsorption, weakened the adsorption of the linear CO species, and created a broad new absorption band with a maximum near 1715 cm{sup {minus}1}; this new low-frequency band is thought to be due to a tilted Rh-C-O-Mn species. On the promoted catalyst both the new low-frequency species and the linear CO species react with hydrogen much more rapidly than does the linear species on the unpromoted catalyst. Additionally, the promoted catalyst does not chemisorb CO at 80 K; adsorption on this catalyst is an activated process, and maximum adsorption is observed only when the sample is exposed to CO at 373 K. This increase in adsorption is believed to be caused by a reconstruction of the manganese oxide overlayer.