Effect of adsorbed layers on the anodic oxidation of simple organic compounds. Part 3.—Cu adsorption on Pt and its effect on the oxidation of HCOOH
- 1 January 1971
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Transactions of the Faraday Society
- Vol. 67, 809-818
- https://doi.org/10.1039/tf9716700809
Abstract
The adsorption and desorption of Cu on a smooth Pt electrode from 1 M H2SO4 solutions which contain a range of Cu2+ concentrations has been studied as a function of potential. The effect of adsorbed Cu on the oxidation rate of HCOOH has been examined at + 0.60 V (RHE). Cu2+ adsorption is controlled largely by an activation process. The slow step in the process is apparently the discharge of Cu2+ at the electrode to Cu+. Desorption of a preadsorbed Cu layer (+0.40 V) is extremely rapid at potentials+ 0.70 V, where no Cu2+ adsorption is normally found. Analysis of the oxidation state of the adsorbing layer by charge and coverage measurements yields a value of 1.92 electrons/site. This indicates that the major part of the layer is Cuads attached to a single Pt surface site. The rate of adsorption of Cu2+ is decreased slightly in the presence of 0.1 M HCOOH. At low coverages (θCu ads 0.19), a slight enhancement of the HCOOH oxidation rate is observed at +0.60 V. Above this coverage, the oxidation process is inhibited. Results are interpreted in terms of Cu2+ adsorption mechanisms on Pt and the effect of the adsorbed layer on the mechanisms of HCOOH electro-oxidation on Pt.Keywords
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