LATTICE-GAS MODELS OF ADSORPTION IN THE DOUBLE-LAYER

The theory of statistical-mechanical lattice-gas modeling of adsorptio n is reviewed and shown to be applicable to a range of electrochemical problems dominated by effective, lateral adsorbate-adsorbate interact ions. A general strategy for applying the method to specific systems i s outlined, which includes microscopic model formulation, calculation of zero-temperature phase diagrams, numerical calculation of thermodyn amic and structural quantities at non-zero temperatures, and estimatio n of effective, lateral interaction energies that cannot be obtained b y first-principles methods. Phenomena that are discussed include poiso ning and enhanced adsorption, and illustrative applications to specifi c systems are reviewed. Particular problems considered are: the poison ing by sulfur of hydrogen adsorption on platinum(lll), the electrochem ical adsorption of naphthalene on polycrystalline copper and of urea o n single-crystal platinum(100), and the underpotential deposition of c opper cn single-crystal gold(lll). Copyright (C) 1996 Elsevier Science Ltd.