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Theoretical study of pattern formation during the catalytic oxidation of CO on Pt{100} at low pressures

Anghel, AT, Hoyle, RB, Irurzun, IM, Proctor, MRE and King, DA (2007) Theoretical study of pattern formation during the catalytic oxidation of CO on Pt{100} at low pressures JOURNAL OF CHEMICAL PHYSICS, 127 (16). ? - ?. ISSN 0021-9606

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Abstract

Theoretical studies have thus far been unable to model pattern formation during the reaction in this system on physically feasible length and time scales. In this paper, we derive a computational reaction-diffusion model for this system in which most of the input parameters have been determined experimentally. We model the surface on a mesoscopic scale intermediate between the microscopic size of CO islands and the macroscopic length scale of pattern formation. In agreement with experimental investigations [M. Eiswirth et al., Z. Phys. Chem., Neue Folge 144, 59 (1985)], the results from our model divide the CO and O-2 partial pressure parameter space into three regions defined by the level of CO coverage or the presence of sustained oscillations. We see CO fronts moving into oxygen-covered regions, with the 1 x 1 to hex phase change occurring at the leading edge. There are also traveling waves consisting of successive oxygen and CO fronts that move into areas of relatively high CO coverage, and in this case, the phase change is more gradual and of lower amplitude. The propagation speed of these reaction waves is similar to those observed experimentally for CO and oxygen fronts [H. H. Rotermund , J. Chem. Phys. 91, 4942 (1989); H. H. Rotermund , Nature (London) 343, 355 (1990); J. Lauterbach and H. H. Rotermund, Surf. Sci. 311, 231 (1994)]. In the two-dimensional version of our model, the traveling waves take the form of target patterns emitted from surface inhomogeneities.

Item Type: Article
Uncontrolled Keywords: Science & Technology, Physical Sciences, Physics, Atomic, Molecular & Chemical, Physics, KINETIC OSCILLATIONS, SELF-ORGANIZATION, SURFACE-REACTION, MOLECULAR-BEAM, PLATINUM, COOXIDATION, ADSORPTION, DYNAMICS
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Divisions: Faculty of Engineering and Physical Sciences > Mathematics
Depositing User: Mr Adam Field
Date Deposited: 27 May 2010 14:07
Last Modified: 23 Sep 2013 18:27
URI: http://epubs.surrey.ac.uk/id/eprint/295

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