Catalytic oxidation of carbon monoxide over Rh/SiO/sub 2/. An in situ infrared and kinetic study

Journal Article · Wed Feb 29 23:00:00 EST 1984 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j150649a015· OSTI ID:6697840

Kiss, J T; Gonzalez, R D

The oxidation of CO on Rh/SiO/sub 2/ has been studied by using an in situ infrared cell reactor. The catalytic activity for the rate of CO oxidation was shown to decrease in the sequence Rh(0) > Rh(I) > Rh(Iapprox.III). The results of a temperature-programmed-oxidation study show that both linearly adsorbed (2065 cm/sup -1/) and bridge-bonded (1920 cm/sup -1/) CO react with O/sub 2/ at a faster rate than the CO dicarbonyl species (2092, 2033 cm/sup -1/). A higher oxidation state of Rh, presumably Rh(Iapprox.III), which gave rise to an adsorbed CO species absorbing at 2103 cm/sup -1/, was found to be relatively inactive. The results of a temperature-programmed-reduction study show that the adsorbed CO dicarbonyl species can be converted into the linearly adsorbed species by the addition of H/sub 2/ at room temperature. Unlike Ru/SiO/sub 2/ and Pt/SiO/sub 2/, reaction rate hysteresis did not occur. However, in an oxygen-rich reactant gas mixture, some modification of the reaction rate did occur as a result of the formation of Rh(I). This led to a modest catalyst deactivation. Both heat-transfer effects and diffusion-controlled processes occur at high CO conversions. Meaningful kinetic parameters can only be obtained by considering steady-state conversions which are less than 10%.

• Research Organization: Univ. of Rhode Island, Kingston
• OSTI ID: 6697840
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 88:5; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSIS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
DATA
ELEMENTS
EXPERIMENTAL DATA
INFORMATION
METALS
MINERALS
NUMERICAL DATA
OXIDATION
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
RHODIUM
SILICA
SILICON COMPOUNDS
SILICON OXIDES
TRANSITION ELEMENTS