Monte Carlo simulations of Underpotential Deposition of Metal Layers on Metal Substrates: Phase Transitions and Critical Phenomena

M.C. GIMÉNEZ; E.P.M. LEIVA; E.V. ALBANO

Modern Aspects of Electrochemistry, Vol 44

Springer, Heidelberg

Año: 2009; p. 1 - 34

The adsorption of a metal monolayer or submonolayer for the systems Ag/Au(100), Au/Ag(100), Ag/Pt(100), Pt/Ag(100), Au/Pt(100), Pt/Au(100), Au/Pd(100) and Pd/Au(100) was studied by means of lattice Monte Carlo simulations. It was found that for some systems, the adsorbate atoms successively occupy kink sites, step sites and the complete monolayer. On the other hand, for other systems, we observe 2-D alloys between substrate and adsorbate-type atoms. In particular, based on the fact that the underpotential deposition of Ag atoms on the $Au(100)$ surface exhibits sharp first-order phase transition at well defined values of the (coexistence) chemical potential ($\mu_{coex}$), we have also performed extensive simulations aimed to investigate the hyteretic dynamic behavior of the system close to coexistence upon the application of a periodic signal