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

Theoretical study of pattern formation during the catalytic oxidation of CO on Pt{100} at low pressures
Theoretical study of pattern formation during the catalytic oxidation of CO on Pt{100} at low pressures
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 Folge144, 59 (1985)], the results from our model divide the CO and O2 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 1×1 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 et al., J. Chem. Phys.91, 4942 (1989); H. H. Rotermund et al., 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
0021-9606
164711
Anghel, Alexandra T.
deae5de5-1b32-421b-840c-3960efa40dda
Hoyle, Rebecca B.
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Irurzun, Isabel M.
bf4c14f7-8d50-404a-a2c1-f18310ccca3e
Proctor, Michael R.E.
226e900f-9137-4230-a468-d726e29c7d30
King, David A.
34fc305f-e722-4ed8-8788-a73b9687aadc
Anghel, Alexandra T.
deae5de5-1b32-421b-840c-3960efa40dda
Hoyle, Rebecca B.
e980d6a8-b750-491b-be13-84d695f8b8a1
Irurzun, Isabel M.
bf4c14f7-8d50-404a-a2c1-f18310ccca3e
Proctor, Michael R.E.
226e900f-9137-4230-a468-d726e29c7d30
King, David A.
34fc305f-e722-4ed8-8788-a73b9687aadc

Anghel, Alexandra T., Hoyle, Rebecca B., Irurzun, Isabel M., Proctor, Michael R.E. and King, David A. (2007) Theoretical study of pattern formation during the catalytic oxidation of CO on Pt{100} at low pressures. The Journal of Chemical Physics, 127 (16), 164711. (doi:10.1063/1.2796174).

Record type: Article

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 Folge144, 59 (1985)], the results from our model divide the CO and O2 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 1×1 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 et al., J. Chem. Phys.91, 4942 (1989); H. H. Rotermund et al., 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

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Accepted/In Press date: 18 September 2007
Published date: 25 October 2007
Organisations: Mathematical Sciences

Identifiers

Local EPrints ID: 380232
URI: https://eprints.soton.ac.uk/id/eprint/380232
ISSN: 0021-9606
PURE UUID: a0e55e30-88f9-4945-af8c-6d82c8309649
ORCID for Rebecca B. Hoyle: ORCID iD orcid.org/0000-0002-1645-1071

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Date deposited: 10 Aug 2015 10:57
Last modified: 20 Jul 2019 00:46

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Contributors

Author: Alexandra T. Anghel
Author: Isabel M. Irurzun
Author: Michael R.E. Proctor
Author: David A. King

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