Surface chemistry models of carbon monoxide oxidation on supported platinum catalysts

Journal Article · Wed Oct 01 04:00:00 EDT 1980 · J. Catal.; (United States)

DOI:https://doi.org/10.1016/0021-9517(80)90306-1· OSTI ID:6570216

Herz, R K; Marin, S P

Rats of CO oxidation on noble metal catalysts are often represented by a Langmuir-Hinshelwood rate expression that assumes the competitive equilibrium adsorption of CO and O/sub 2/ on the active metalsurface. Surface chemistry studies reported in the literature have shown, however, that this assumption cannot be justified under all conditions. As a result, the usual Langmuir-Hinshelwood rate expression is unable to explain the data of several reported studies of CO oxidation on Pt catalyts. Development of two reaction models which include separate adsorption, desorption, and surface reaction steps, and which do not assume adsorption equilibrium is reported. The ability of each model to fit CO oxidation rate data taken with an alumina-supported Pt catalyst is compared with that of the usual Langmuir-Hinshelwood rate expression. Unlike the usual rate expression, the surface chemistry model successfully simulate the abrupt transition in steady-state rate that occurs between the CO inhibition regime and the first-order regime. The parameter values used to fit the supported Pt data are similar to those determined with Pt crystals. However, they indicate that CO may be adsorbed less strongly on the supported Pt nd that most of the surface Pt atoms in the supported catalyst were deactivated by an oxidizing pretreatment.

• Research Organization: General Motors Research Lab., Warren, MI
• OSTI ID: 6570216
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 65:2; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

500200* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
ELEMENTS
MATHEMATICAL MODELS
METALS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PLATINUM
PLATINUM METALS
TRANSITION ELEMENTS