Lattice gas model for CO electrooxidation on Pt-Ru bimetallic surfaces

Journal Article · Thu Jul 01 04:00:00 EDT 1999 · Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical

DOI:https://doi.org/10.1021/jp990520k· OSTI ID:682081

Koper, M T.M.; Jansen, A P.J.; Santen, R.A. van ^[1]; Lukkien, J J ^[2]

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1. Schuit Inst. of Catalysis, Eindhoven (Netherlands). Lab. of Inorganic Chemistry and Catalysis
2. Eindhoven Univ. of Technology (Netherlands). Dept. of Mathematics and Computing Science

The authors propose a lattice gas model for the carbon monoxide oxidation on platinum-ruthenium electrode surfaces. The kinetic model includes the main mechanistic bifunctional features as they are generally agreed upon in the literature. The CO stripping voltammetry is solved by dynamic Monte Carlo simulations. For a randomly dispersed alloy of Ru and Pt, the model gives a satisfactory semiquantitative agreement with the experimental CO stripping results of Gasteiger et al. [Journal of Physical Chemistry 1994, 98, 617]. It is shown how the bifunctional mechanism cannot operate if CO is not mobile on the surface, and a simple Tafel-type experiment with a low concentration of active Pt-Ru sites is suggested to check quantitatively the Co mobility rate. On a surface with large Ru islands, the overpotential for CO oxidation increases, and two CO stripping peaks may appear if the CO mobility is sufficiently low. A mean-field model of the system reproduces the DMC results for high CO mobility but breaks down for a system with large Ru islands and a comparatively low CO surface diffusion constant.

• OSTI ID: 682081
• Journal Information: Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical, Journal Name: Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical Journal Issue: 26 Vol. 103; ISSN 1089-5647; ISSN JPCBFK
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
BIMETALS
CARBON MONOXIDE
ELECTRODES
FUEL CELLS
MONTE CARLO METHOD
PLATINUM
RUTHENIUM
VOLTAMETRY