The surface diffusion of gold atoms on gold electrodes in acid solution and its dependence on the presence of foreign adsorbates

The surface diffusion coefficient (D<sub>s</sub>) of Au atoms in 0.5 M H<sub>2</sub>SO<sub>4</sub> at 298 K has been determined from the time dependence of the surface roughness factor of electrodispersed Au electrodes in 0.5 M H<sub>2</sub>SO<sub&g...

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Detalles Bibliográficos
Autores principales:	Alonso, C., Salvarezza, Roberto Carlos, Vara, J. M., Arvia, Alejandro Jorge
Formato:	Articulo
Lenguaje:	Inglés
Publicado:	1990
Materias:	Ciencias Exactas Química surface diffusion Adsorción adsorbate electrodispersed electrodes Electrodos Oro
Acceso en línea:	http://sedici.unlp.edu.ar/handle/10915/79960
Aporte de:	SEDICI (UNLP) de Universidad Nacional de La Plata

Descripción
Sumario:	The surface diffusion coefficient (D<sub>s</sub>) of Au atoms in 0.5 M H<sub>2</sub>SO<sub>4</sub> at 298 K has been determined from the time dependence of the surface roughness factor of electrodispersed Au electrodes in 0.5 M H<sub>2</sub>SO<sub>4</sub>. The value of D<sub>s</sub> for 0.5 M H<sub>2</sub>SO<sub>4</sub> is 5 × 10<sup>−14</sup> cm<sup>2</sup> s<sup>−1</sup>, a figure which depends considerably on the presence of adsorbable species in solution. Thus, the adsorption of pyridine produces a remarkable decrease of D<sub>s</sub>, whereas the adsorption of Cl<sup>−</sup> ion results in the opposite effect. The corresponding values of D<sub>s</sub> are 1.2 × 10<sup>−14</sup> cm<sup>2</sup> s<sup>−1</sup> for 0.5 M H<sub>2</sub>SO<sub>4</sub> + 0.1 M pyridine, and 2.5 × 10<sup>−13</sup> cm<sup>2</sup> s<sup>−1</sup> for 0.5 M H<sub>2</sub>SO<sub>4</sub> + 5 × 10<sup>−4</sup> M KCl. These results are interpreted through the influence of the adsorbate on the Au surface atom diffusion mechanism.