Spontaneous Deposition of Ag. Influence of Composition of Ag-Containing Solution on the Electrocatalytic Activity of Pt-Modified Surface

SILVANA A. MARTÍNEZ ; MARÍA E. MARTINS ; CARLOS F. ZINOLA

ELECTROCATALYSIS

SPRINGER

Año: 2011

1868-2529

Using spontaneous and electrochemical deposition of Ag, Ag-covered Pt polycrystalline electrodes were prepared. The behavior of these Pt-based composite catalysts depends on their morphology, the crystalline and electronic properties, and in a minor extent, the solution composition containing Ag ion. This work deals with the study of methanol and carbon monoxide electrooxidation using Pt surfaces modified by Ag through spontaneous deposition. The main objective is to investigate the influence of the counterion nature of Ag-containing electrolytic solutions. For this purpose, the electrooxidation of methanol adsorbed residues and also of carbon monoxide was studied applying conventional electrochemical methods in aqueous 1 M H2SO4. Those reactions exhibit different behavior which is highly dependent on the nature of the Ag-containing electrolytic solution used to carry out the deposition process. The results demonstrate that in the adsorption process of both methanol residues and carbon monoxide, the interaction with Pt surface is achieved through electrodeposited Ag, but the counterion plays a significant role. A theoretical model is proposed in which it is considered the coadsorption of the counterion with water molecules preadsorbed on Pt surface and the interaction of the anions with residues adsorbed from carbon monoxide and methanol.