Reactivity and microstructure of Rh and Rh-Ce in NO + CO

Journal Article · Fri Jul 01 04:00:00 EDT 1994 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1006/jcat.1994.1181· OSTI ID:6859355

Schwartz, J M; Schmidt, L D ^[1]

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1. Univ. of Minnesota, Minneapolis, MN (United States)

Changes in the activity and selectivity of Rh and Rh-Ce catalysts supported on Al[sub 2]O[sub 3] and SiO[sub 2] in the NO + CO reaction have been measured as a function of pretreatment. Rh-Ce/Al[sub 2]O[sub 3] had very low activity following a pretreatment in H[sub 2], which increased by a factor of [approximately]10 after heating in NO, and increased further in CO and in NO + CO. Rh-Ce catalysts also had very low N[sub 2] selectivity vs N[sub 2]O after treatments in H[sub 2], CO, and NO + CO, but not after heating in air or NO, and had a lower activation energy for NO reduction than Rh catalysts. The activities of Rh/Al[sub 2]O[sub 3] and Rh/SiO[sub 2] catalysts correlate well with changes in microstructures. An increased dispersion produced an increased activity at low temperatures except for the air pretreatment which oxidized the Rh and produced the lowest activity. Selectivity to N[sub 2] increased with increasing temperature below 300[degrees]C up to 100% for all pretreatments. All changes on alumina supported catalysts were reversible. The activity of Rh/SiO[sub 22] decreased after heating in NO + CO because of volatilization of Rh. 22 refs., 6 figs.

• OSTI ID: 6859355
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 148:1; 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
ACTIVATION ENERGY
ALLOYS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYST SUPPORTS
CATALYTIC EFFECTS
CERIUM ALLOYS
CHALCOGENIDES
CHEMICAL REACTIONS
ELEMENTS
ENERGY
METALS
MICROSTRUCTURE
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN OXIDES
OXIDES
OXYGEN COMPOUNDS
PLATINUM METAL ALLOYS
PLATINUM METALS
RARE EARTH ALLOYS
RHODIUM
RHODIUM ALLOYS
SILICON COMPOUNDS
SILICON OXIDES
TRANSITION ELEMENTS