Effect of adsorbed layers on the anodic oxidation of simple organic compounds. Part 4.—Ag adsorption on Pt and its effect on HCOOH oxidation
- 1 January 1971
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Transactions of the Faraday Society
- Vol. 67, 819-827
- https://doi.org/10.1039/tf9716700819
Abstract
The adsorption of Ag on a smooth Pt electrode in 1 M H2SO4 at 40°C has been studied from 0.45 to 0.75 V (RHE) in solutions varying from 10–4 to 10–6 M. The effect of adsorbed Ag on the oxidation rate of HCOOH has been examined at 0.65 and 0.75 V. A diffusion-limited adsorption process is indicated. Analysis of the oxidation state of the adsorbed layer to θAg ads= 0.59 yields a value of 0.77 electrons/site. Above this coverage, a value of 1.97 electrons/site is obtained. This suggests, in the former case, a mixed layer composed of Ag singly bonded to a single Pt site with some single bonding to two Pt sites. At the higher coverages, two Ag atoms are apparently attached to a single Pt surface site. The rate of adsorption of Ag+ is decreased by the presence of HCOOH. Below θAg ads∼0.40, the oxidation rate of HCOOH is enhanced compared with that of an electrode partially covered with adsorbed HCOOH intermediates. Above this coverage, the oxidation is inhibited.Keywords
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