Oscillatory oxidation of CO over Pt at pressures from 10 to 760 Torr

Journal Article · Fri Feb 01 04:00:00 EST 1991 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1016/0021-9517(91)90181-3· OSTI ID:5548467

Tsai, P K; Wu, M G; Maple, M B ^[1]

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1. Univ. of California, San Diego (USA)

Oscillations in the rate of CO oxidation over polycrystalline Pt have been measured at total pressures of 760 and 10 Torr. Despite the pressure change of two orders of magnitude, oscillations occurred between similar values of high and low reactivity, and over roughly the same experimental parameters. The lack of dependence of the reaction kinetics on the pressure is not predicted by the Langmuir-Hinshelwood equations that provide the rate multiplicities underlying the oscillations in a number of recent models. This lack of agreement suggests that the current understanding of CO oxidation and oscillatory reaction kinetics remains incomplete. The primary difference between the oscillations at the two pressures occurred in the waveforms, which were highly structured and fractal-like at P = 760 Torr, and became simple square waves on the evolved catalyst surface at P = 10 Torr. Differences in the catalyst surface structure and in coupling between parts of the catalyst through concentration gradients in the gas may account for these changes in the complexity of the waveforms.

• OSTI ID: 5548467
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 127:2; ISSN 0021-9517; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330702 -- Emission Control-- Carbon Monoxide
54 ENVIRONMENTAL SCIENCES
540120* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
AIR POLLUTION CONTROL
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CONTROL
CRYSTALS
ELEMENTS
EQUATIONS
FRACTALS
KINETIC EQUATIONS
KINETICS
METALS
OSCILLATIONS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PLATINUM
PLATINUM METALS
POLLUTION CONTROL
POLYCRYSTALS
PRESSURE DEPENDENCE
REACTION KINETICS
TRANSITION ELEMENTS