Evidence for a second CO oxidation mechanism on Rh/ceria

Journal Article · Wed Sep 01 04:00:00 EDT 1993 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1006/jcat.1993.1255· OSTI ID:5772357

Zafiris, G S; Gorte, R J ^[1]

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1. Univ. of Pennsylvania, Philadelphia, PA (United States)

The reaction properties of ceria-supported Rh for CO oxidation were investigated using model catalysts prepared by vapor deposition of Rh onto flat, low-surface-area ceria. Steady-state reaction rates were measured on this catalyst at 573 K for O[sub 2] pressures between 0.1 and 8 Torr and for CO pressures between 0.1 and 600 Torr, and the rates were compared to those measured on Rh/[alpha]-Al[sub 2]O[sub 3](0001). The rates for Rh/ceria and Rh/[alpha]-Al[sub 2]O[sub 3](0001) are essentially identical over most of the pressure ranges studied, with the reaction order for CO being inverse first-order under reducing conditions. However, for higher CO pressures, the reaction becomes zeroth-order in CO on Rh/ceria. It is suggested that this is due to a second reaction mechanism involving oxygen migration from ceria to the Rh, which had previously been observed in temperature-programmed desorption measurements on the same model catalysts. 23 refs., 3 figs.

• OSTI ID: 5772357
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 143:1; ISSN 0021-9517; ISSN JCTLA5
• 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
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CERIUM COMPOUNDS
CERIUM OXIDES
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
ELEMENTS
HETEROGENEOUS CATALYSIS
KINETICS
MEDIUM VACUUM
METALS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
PRESSURE DEPENDENCE
RARE EARTH COMPOUNDS
REACTION KINETICS
RHODIUM
SURFACE AREA
SURFACE PROPERTIES
TRANSITION ELEMENTS