COMPUTATIONAL LATTICE-GAS MODELING OF THE ELECTROSORPTION OF SMALL MOLECULES AND IONS

SURFACE SCIENCE

卷:335

Article; Proceedings Paper

RIKVOLD, PA ; GAMBOAALDECO, M ; ZHANG, J ; HAN, M ; WANG, Q ; RICHARDS, HL ; WIECKOWSKI, A

关键词: CHEMISORPTION;    COMPUTER SIMULATIONS;    CONSTRUCTION AND USE OF EFFECTIVE INTERATOMIC INTERACTIONS;    ELECTROCHEMICAL METHODS;    EQUILIBRIUM THERMODYNAMICS AND STATISTICAL MECHANICS;    LOW INDEX SINGLE CRYSTAL SURFACES;    SOLID-LIQUID INTERFACES;    SURFACE THERMODYNAMICS;   

DOI  :  10.1016/0039-6028(95)00440-8

来源: Elsevier

【 摘 要 】

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 systems involve the specific adsorption of small molecules or ions on single-crystal electrodes, and they are characterized by 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, signalled in cyclic voltammograms by a sharp current peak. Based on data from in situ radiochemical surface concentration measurements, cyclic voltammetry, and scanning tunneling microscopy, and 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 calculations and numerical Monte Carlo simulations, and effective lattice-gas interaction parameters were determined so as to provide agreement with the experimental results.

【 授权许可】

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