Computational Lattice-Gas Modeling of the Electrosorption of Small Molecules and Ions

P. A. Rikvold; M. Gamboa-Aldeco; J. Zhang; M. Han; Q. Wang; H. L. Richards; A. Wieckowski

doi:10.1016/0039-6028(95)00440-8

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Computational Lattice-Gas Modeling of the Electrosorption of Small Molecules and Ions

P. A. Rikvold·M. Gamboa-Aldeco·J. Zhang·M. Han·Q. Wang·H. L. Richards·A. Wieckowski

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Abstract

We present two recent applications of lattice-gas modeling techniques to electrochemical adsorption on catalytically active metal substrates: urea on Pt(100) and (bi)sulfate on Rh(111). Both involve the specific adsorption of small molecules or ions on well-characterized single-crystal electrodes, and they provide a particularly good fit between the adsorbate geometry and the substrate structure. The close geometric fit facilitates the formation of ordered submonolayer adsorbate phases in a range of electrode potential positive of the range in which an adsorbed monolayer of hydrogen is stable. In both systems the ordered-phase region is separated from the adsorbed- hydrogen region by a phase transition, signified in cyclic voltammograms by a sharp current peak. Based on data from {\it in situ\/} radiochemical surface concentration measurements, cyclic voltammetry, and scanning tunneling micro- scopy, and {\it ex situ\/} Auger electron spectroscopy and low-energy electron diffraction, we have developed specific lattice-gas models for the two systems. These models were studied by group-theoretical ground-state calcu- lations and numerical Monte Carlo simulations, and effective lattice-gas inter- action parameters were determined so as to provide agreement with experiments.

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P. A. Rikvold, M. Gamboa-Aldeco, J. Zhang, M. Han, Q. Wang, H. L. Richards, A. Wieckowski. 1994-09-29. Computational Lattice-Gas Modeling of the Electrosorption of Small Molecules and Ions. https://doi.org/10.1016/0039-6028(95)00440-8

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