The effect of ceria on the adsorption and reaction properties of Pt and Rh

Conference · Fri Dec 31 04:00:00 UTC 1993

OSTI ID:142011

Zafiris, G S; Gorte, R J ^[1]

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

The adsorption and reaction properties of ceria-supported, Pt and Rh catalysts were studied on model catalysts prepared by vapor depositing small metal particles onto flat, ceria substrates. Adsorption properties were characterized as a function of particle size using TPD of NO and CO in ultrahigh vacuum, and reaction properties for NO reduction by CO were measured on the same Rh samples at 10 torr each of NO and CO. Interactions between Pt and ceria were found to be relatively weak, and TPD results for both NO and CO were found to be identical to previous results on Pt/alumina for a given particle size. The results for Rh ceria were significantly different. TPD of CO from Rh/ceria yielded significant amounts of CO{sub 2}, with simultaneous reduction of near-surface ceria. TPD curves for NO exhibited significantly more N{sub 2} desorption in the low-temperature region compared to Rh/alumina. While NO reduction by CO is shown to be strongly affected by Rh particle size on alumina, support composition is also shown to significantly affect the rate. Furthermore, it is shown that the high-pressure reaction rates can be understood from the low-pressure TPD curves.

• OSTI ID: 142011
• Report Number(s): CONF-930304--
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
CARBON MONOXIDE
CATALYST SUPPORTS
CATALYTIC EFFECTS
CERIUM OXIDES
NITRIC OXIDE
PLATINUM
REDUCTION
RHODIUM
SORPTIVE PROPERTIES