Producción Científica Profesorado

THEORETICAL STUDY ON THE MODIFICATION OF ACTIVE SITES IN GOLD SURFACES MODELED AS FINITE CLUSTERS: INFLUENCE OF STRUCTURAL DEFECTS AND THE APPLIED OVERPOTENTIAL



Mendoza Huizar, Luis Humberto

2000

Theoretical study on the modification of active sites in gold surfaces modelled as finite clusters. LUIS H. MENDOZA-HUIZAR, JUVENCIO ROBLES , JUAN SILVA DOMINGUEZ


Abstract


We report a description of the reactivity of a gold surface from theoretical calculations. This surface has been modeled with finite clusters, keeping the fcc crystal structure. The clusters are built with one, two or four unit cells. The influence exerted by structural defects and excess charge (to model an applied overpotential), on the density distribution in the surface, is analyzed. To describe the surface reactivity we employ reactivity indices from Density Functional Theory such as the Fukui functions and the condensed local softnesses. These were computed at an abinitio Hartree-Fock level, using the pseudopotentials of Hay and Wadt. From our numerical results we can conclude that the active sites may be clearly defined and pin-pointed. The cluster charge substantially modifies the distribution and position of the active sites, leading to changes in the active sites distribution from on top to on hollow or on bridge positions, depending on the cluster charge. Furthermore, it is observed that the presence of structural defects greatly modify the HOMO density close to the defect and this can be used to explain to some extent the superficial diffusion phenomenon experimentally observed, as well as the adsorption of ions in some specific surface sites.



Producto de Investigación




Artículos relacionados

Influence of the Cation Nature of the Sulphate Salt on the Electrochemical Synthesis of Sulfate-Dope...

Do Spiroarsoranes Exhibit Polytopal Equilibrium in Solution?

Mercury Ions Removal from Aqueous Solution Using an Activated Composite Membrane

Analysis of the experimental pressuretemperature behavior in the isotropicnematic phase transition f...

Estudio de las Interacciones Ácido Húmico-Metales Pesados y Determinación de sus Constantes de Estab...

ELECTROCHEMICAL STUDY ABOUT ZINC ELECTRODEPOSITION ONTO GCE AND HOPG SUBSTRATES

Effect of TiO2-Al2O3 sol-gel supports on the superficial Ni and Mo species in oxidized and sulfided ...

Synthesis of Zn compounds derived from 1H-benzimidazol-2-ylmethanamine

A Voltammetric Study Of The Underpotential Deposition Of Cobalt Onto A Glassy Carbon Electrode

Hydrogen bond studies in substituted N-(2-hydroxyphenyl)--2-[(4-methylbenzenesulfonyl)amino]acetamid...