Platinum carbon monoxide oxidation over

However, the analysis of the data was carried out in such a way as to cast doubt on the validity of these conclusions (Vayenas54). Okamoto, Kawamura and Kudo48 went on to use the e.m.f. interpretation from the above work49 to further investigate the mechanism of CO oxidation over platinum by using the cell as a probe of the surface coverage of carbon monoxide. 

Metcalfe and Sundaresan15 went on to confirm that e.m.f. s obtained in the case of CO oxidation over platinum cannot be explained if reaction (3.3) is the only electrochemical reaction to occur. Even under oxygen rich conditions, carbon monoxide was involved in the electrochemical reactions, the dominant electrochemical reactions being,15... 

Goodman, M. G., Kenney, C. N., Morton, W., Cutlip, M. B. and Mukesh, D., 1982, Transient studies of carbon monoxide oxidation over platinum catalyst. Surf. ScL 120, L453-460. 

Now possibilities of the MC simulation allow to consider complex surface processes that include various stages with adsorption and desorption, surface reaction and diffusion, surface reconstruction, and new phase formation, etc. Such investigations become today as natural analysis of the experimental studying. The following papers [282-285] can be referred to as corresponding examples. Authors consider the application of the lattice models to the analysis of oscillatory and autowave processes in the reaction of carbon monoxide oxidation over platinum and palladium surfaces, the turbulent and stripes wave patterns caused by limited COads diffusion during CO oxidation over Pd(110) surface, catalytic processes over supported nanoparticles as well as crystallization during catalytic processes. 

Gavril, D. Katsanos, N.A. Karaiskakis, G. Gas chromatographic kinetic study of carbon monoxide oxidation over platinum-rhodium catalysts. J. Chromatogr., A 1999, 852, 507-523. 

F.H.M. Dekker, J.G. Nazloomian, A. Bliek, F. Kapteijn, J.A. Moulijn, D.R. Coulson, P.L. Mills, and J.J. Lerou, Carbon Monoxide Oxidation over Platinum powder A comparison of TAP and Step-Response Experiments, Appl. Catal. A, accepted for publication (1996). 

Classical analysis has demonstrated that a given quantity of active material should be deposited over the thinnest layer possible in order to minimize diffusion limitations in the porous support. This conclusion may be invalid for automotive catalysis. Carbon monoxide oxidation over platinum exhibits negative order kinetics so that a drop in CO concentration toward the interior of a porous layer can increase the reaction rate and increase the effectiveness factor to above one. The relative advantage of a thin catalytic layer is further reduced when one considers its greater vulnerability to attrition and to the deposition of poisons. 

The results reported in the literature are contradictory difficult to compare. In spite of the multitude of experimental studies there are only few cases where representative rate coefficients can be derived from the published data. Even then, the catalysts used in those investigations are quite different in nature and the domains of temperature and/or reactant concentrations explored remain small. It is therefore the scope of the present study to reexamine the oxidation of the carbon monoxide by oxygen over platinum, palladimn and rhodium in a wide range of temperature and pressure and to compare the results with available literature data in order to solve the existing discrepancies. 

Igarashi H., Uchida H., Suzuki M., Sasaki Y. and Watanabe M. 1997. Removal of carbon monoxide from hydrogen-rich fuels by selective oxidation over platinum catalyst supported on zeolite, Appl. Catal. A, 159, 159-169. 

Source From Gas chromatographic kinetic study of carbon monoxide oxidation over platinum-rhodium catalysts, in J. Chromatogr. 

Fig. 4 Energy distribution function, (p(e t) (cmol/kJ/mol/), against the dimensionless product of the lateral interaction energy (P) and the local isotherm (0)P0, for carbon monoxide adsorption over a bimetalhc Pto.25-Rho.75 silica supported catalyst, at 698 K. Source From Gas chromatographic kinetic study of carbon monoxide oxidation over platinum-rhodium catalysts, in J. Chromatogr.

Engel, T. Ertl, G. Advances in Catalysis, Academic Press, New York, (1979). Cant, N. W. Metal crystalhte size effects and low-temperature deactivation in carbon monoxide oxidation over platinum. Journal of Catalysis 62, 173-175 (1980). 

Akubuiro, E. C., Verykios, X. E. Lesnick, L. Dispersion and snpport effects in carbon monoxide oxidation over platinum. App/ied Catalysis 14, 215-227 (1985). Stara, L, Nehasil, V. MatoUn, V. The influence of particle size on CO oxidation on Pd/alumina model catalyst. Surface Science 331—333, 173—177 (1995). 

Mukesh, D., Cutlip, M.C., Goodman, M., Kenney, C.N., Morton, W., 1982. The stability and oscillations of carbon monoxide oxidation over platinum supported catalyst. Effect of butene. Chem. Eng. Sci. 37, 1807-1810. Mukesh, D., Kenney, C.N., Morton, W., 1983. Concentration oscillations of carbon monoxide, oxygen and 1-butene over a platinum supported catalyst. Chem. Eng. Sci. 38, 69-77. 

The low-temperature fuel cells (PEMFC and PAFC) require pure hydrogen, as carbon monoxide is a poison to the platinum anode. A PSA unit as used in large-scale hydrogen plants (Figure 2.4) carmot be used at the small scale in question, and the final purifrcation is made either by methanation (as used in ammonia plants, Section 2.5) or by preferential partial oxidation (PROX) of carbon monoxide to carbon dioxide over a... 

Zheng X, Mantzaras J, Bombach R Kinetic interactions between hydrogen and carbon monoxide oxidation over platinum. Combust Flame 161 332—346, 2014. 

Akubuiro EC, Verykios XE, Lesnick L. Dispersion and support effects in carbon monoxide oxidation over platinum. Appl Catal. 1985 14 215. 

A sophisticated quantitative analysis of experimental data was performed by Voltz et al. (96). Their experiment was performed over commercially available platinum catalysts on pellets and monoliths, with temperatures and gaseous compositions simulating exhaust gases. They found that carbon monoxide, propylene, and nitric oxide all exhibit strong poisoning effects on all kinetic rates. Their data can be fitted by equations of the form ... 

Houdry s solution to the problem was the first catalytic converter ever designed for an automotive vehicle. The catalytic converters found on almost all cars and trucks in use today are still strikingly similar to his invention. Exhaust gases passed into the converter and over a bed of platinum catalyst, then exited with a greatly reduced concentration of carbon monoxide, nitrogen oxides, and unburned hydrocarbons. Houdry obtained a patent for his device in 1956 and founded a company, Oxy-Catalyst, to manufacture and sell the new product. 

Potentiometric techniques have been used to study autonomous reaction rate oscillations over catalysts and carbon monoxide oxidation on platinum has received a considerable amount of attention43,48,58 Possible explanations for reaction rate oscillations over platinum for carbon monoxide oxidation include, (i) strong dependence of activation energy or heat of adsorption on coverage, (ii) surface temperature oscillations, (iii) shift between multiple steady states due to adsorption or desorption of inert species, (iv) periodic oxidation or reduction of the surface. The work of Sales, Turner and Maple has indicated that the most... 

Dynamic reactor studies are not new, but they have not been widely used in spite of the fact that they can provide a wealth of information regarding reaction mechanisms. In this research, oxidation of carbon monoxide over supported cobalt oxide (C03O4) was studied by both dynamic and conventional steady state methods. Among metal oxides, cobalt oxide is known to be one of the most active catalysts for CO and hydrocarbon oxidation, its activity being comparable to that of noble metals such as palladium or platinum. 

---