Reaction-diffusion front propagation across stepped surfaces during catalytic oxidation of CO on Pt(100)

authored by: M. Tammaro, J. W. Evans, C. S. Rastomjee, W. Swiech, A. M. Bradshaw, R. Imbihl
Abstract: High-resolution microscopy studies of the removal of CO-adlayers on Pt(100) by exposure to oxygen reveal that reaction-diffusion front propagation is impeded both by mesoscopic step bunches and by monoatomic steps. The resulting "stop-and-go" nature to front propagation can be characterized in terms of a time delay for crossing each step bunch or step, at least when the separation of these defects is comparable to or exceeds the width of the front. Here, we quantify this time delay in terms of the reduced diffusion coefficient for CO in step bunch regions and the width of these regions, or in terms of the reduced hop rate for CO across monoatomic steps. We also briefly examine front propagation across arrays of more closely spaced steps. Results facilitate assessment of terrace diffusivities from average or macroscopic front propagation velocities across multiply stepped surfaces.
Organisation(s): Institute of Physical Chemistry and Electrochemistry
External Organisation(s): University of Rhode Island
Fritz Haber Institute of the Max Planck Society (FHI)
University of Illinois at Urbana-Champaign
Iowa State University
Type: Article
Journal: Surface science
Volume: 407
Pages: 162-170
No. of pages: 9
ISSN: 0039-6028
Publication date: 30.11.1998
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Condensed Matter Physics, Surfaces and Interfaces, Surfaces, Coatings and Films, Materials Chemistry
Electronic version(s): https://doi.org/10.1016/S0039-6028(98)00168-X (Access: Closed)

BibTeX

@article{ab3ff6c8274d49179dcd283156238cd0,
title = "Reaction-diffusion front propagation across stepped surfaces during catalytic oxidation of CO on Pt(100)",
abstract = "High-resolution microscopy studies of the removal of CO-adlayers on Pt(100) by exposure to oxygen reveal that reaction-diffusion front propagation is impeded both by mesoscopic step bunches and by monoatomic steps. The resulting {"}stop-and-go{"} nature to front propagation can be characterized in terms of a time delay for crossing each step bunch or step, at least when the separation of these defects is comparable to or exceeds the width of the front. Here, we quantify this time delay in terms of the reduced diffusion coefficient for CO in step bunch regions and the width of these regions, or in terms of the reduced hop rate for CO across monoatomic steps. We also briefly examine front propagation across arrays of more closely spaced steps. Results facilitate assessment of terrace diffusivities from average or macroscopic front propagation velocities across multiply stepped surfaces.",
keywords = "CO-oxidation, Pt(100), Reaction-diffusion fronts, Steps, Surface diffusion",
author = "M. Tammaro and Evans, {J. W.} and Rastomjee, {C. S.} and W. Swiech and Bradshaw, {A. M.} and R. Imbihl",
note = "Funding Information: The work of M.T. and J.W.E. was supported by the Division of Chemical Sciences, Basic Energy Sciences, USDOE. It was performed at Ames Laboratory, which is operated for the USDOE by Iowa State University under Contract No. W-7405-Eng-82.",
year = "1998",
month = nov,
day = "30",
doi = "10.1016/S0039-6028(98)00168-X",
language = "English",
volume = "407",
pages = "162--170",
journal = "Surface science",
issn = "0039-6028",
publisher = "Elsevier",
number = "1-3",
}