Mechanism carbon monoxide oxidation

Stampfl C and Scheffler M 1997 Mechanism of efficient carbon monoxide oxidation at Ru(OOOI) J. Vac. Sci. Technoi. A 15 1635... 

A similar oxidation-reduction mechanism in the carbon monoxide oxidation reaction on oxide catalysts has been proposed by Benton (71), Bray (72), Frazer (73), and Schwab (74). In this reaction also, Mooi and Selwood (57) found that a decrease in the percentage of iron oxide, manganese oxide or copper oxide on the alumina support first increased the rate, and then at lower percentages decreased the rate, of carbon monoxide oxidation, indicating that valence stabilization is again operative in these cases. 

Just as in the case of the H2-D2 exchange on ZnO, two mechanisms are also discernible for the carbon monoxide oxidation [stage (b)] on nickel oxide below 300°C. There is a low-temperature mechanism operative between 100° and 180°C. characterized by a low activation energy of 2 kcal./mole and a high-temperature mechanism, above 180°C., with a higher activation energy of 13 kcal./mole. The kinetics are different and are respectively ... 

Such a proof of the carbon monoxide oxidation was first given by one of us (28). It is very important to remark that the catalysts containing impurities were prepared by firing together in air at 600°C. for 3 hr. a mechanical mixture of the required components in adequate proportions. As pointed out by Fensham (54), this is much too low a temperature to ensure homogeneous solid solutions. Consequently, when a catalyst is described as NiO + 0.1% Li2O, there is no assurance that this nominal composition is realized at all either in the surface layer or in the bulk of the sample. As will be shown, this reservation is quite essential. 

The Mechanism of Carbon Monoxide Oxidation on Solid Oxides.. 243... 

In the current volume a variety of subjects is treated by competent authors. These subjects deal with new techniques of surface investigations with the microbalance, with the elucidation of reaction mechanisms by the concept of intermediates, and with specialized studies of the ammonia synthesis, hydrogenations, carbon monoxide oxidation and hydrocarbon syntheses. In addition, Volume V contains an extensive critical review of Russian literature in catalysis. 

Seravalli, J., Kumar, M., Lu, W.-P., and Ragsdale, S. W., 1997, Mechanism of carbon monoxide oxidation by the carbon monoxide dehydrogenase/acetyl-CoA syndiase from Clostridium thermoaceticum Kinetic characterization of the intermediates, Biochem. 36 11241fi 11251. 

The oxidahon of carbon monoxide to carbon dioxide using similar bismuth uranate catalysts has been reported by Derouane and coworkers [49]. The work on carbon monoxide oxidation confirmed that the bismuth uranate catalyst operated by a redox mechanism. These studies on bismuth uranates highlight the important role played by oxygen transfer via the lathee, and reinforce the importance of the ability of uranium to exhibit relatively facile redox behavior. 

Examples of catalysts in combustion reaction include the effect of H2O on the carbon monoxide oxidation reaction CO H- 2 C02- Nitric oxide also catalyzes CO oxidation through the mechanism 2 NO 4-O2 2NO2 (overall) and NO2 -f CO NO H- CO2. In both of these examples, an intermediate compound (for example, NO2) is formed and then destroyed. The addition of a small amount of NO2 to an H2 — O2 mixture leads to a branched-chain explosion by introducing the relatively rapid initiation step NO2 H- X NO H- O H- X, with the O atoms so produced generating the usual H2 — O2 chain. The NO2 also participates in the efficient termination step NO2 H- O NO H- O2, which is sufficiently important at large concentrations of NO2 to cause a slow reaction to be... 

In carbon monoxide oxidation, the species X has been identified as the O atom [514, 515], and the observed glows, due to O + CO emission, are an indicator of its concentration history. The scheme proposed by Yang [515] is based on the Brokaw mechanism (see Sect. 10.1.3(a)), and consists of the reactions... 

MECHANISMS OF THE CARBON MONOXIDE OXIDATION AND NITRIC OXIDE REDUCTION REACTIONS OVER SINGLE CRYSTAL AND SUPPORTED RHODIUM CATALYSTS ... 

Mechanisms of the Carbon Monoxide Oxidation and Nitric Oxide Reduction Reactions over Single Crystal and Supported Rhodium Catalysts High Pressure Rates Explained using Ultrahigh Vacuum Surface Science", G.B. Fischer, Se H. Oh, J.E. Carpenter, C.L. DiMaggio, S.J. Schmieg,... 

Surface science studies of thin films may be very helpful for the understanding of the mechanisms of heterogeneous catalysis on intermetallics. This was true in particular for the AES study of the Ru(0001)-Ce-H2 interface performed by Walker and Lambert (1992) in the context of ammonia synthesis or the growth of cerium films on polycrystalline rhodium (Warren et al. 1993) on top of which carbon monoxide oxidation was performed. 

The oxidation of hydrogen catalyzed by finely divided platinum was first observed by Dobereiner in 1823 [75] and prompted Berzelius to introduce the term "catalysis" [76]. One might expect that in this case the mechanism is comparably simple as with carbon monoxide oxidation. Both reactants are known to first adsorb dissociatively. While Oad forms the known 2x2 structure presented several times before, with adsorbed H a problem arises The maximum coverage was found to be one, but no ordered structures could be identified with LEED nor could the adsorbates be identified by STM. This is caused by the fact that this surface is energetically very smooth, and the first vibrational excitations need only a few kj/mol [77-80]. As a consequence, at not extremely... 

The current knowledge of the CO + O2 reaction mechanism makes possible to state rather justified theoretical models giving insight to the features of spatio-temporal dynamics of reaction on the platinum surface. Carbon monoxide oxidation over Pt(lOO) single crystal has been studied comprehensively. It was shown that under certain conditions (partial pressures of reactants and temperature), the adsorbate coverages and the reaction rate undergo self-oscillations attended by the spatio-temporal pattern of COads and Oads formation on the surface [1,2,94]. The observed phenomena are associated with the reversible adsorbate-induced surface phase transition hex 1 X 1. The platinum state in unreconstructed 1x1 phase is catalytically active due to the ease of oxygen molecules dissociation S (02) 0.3—0.4 S (02) 10. The CO... 

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