EDL structure and peculiarities of ferricyanide cyclic voltammetry for silver deposits on gold

• The electric double layer on Ag monolayer at Au is close to that on Ag.
• The kinetics for Fe(CN)63 −/4 − on Ag monolayer at Au corresponds to that on Au.
• For Ag multilayers, silver hexacyanoferrate (II) is formed in K3Fe(CN)6 solution.
• Ag hexacyanoferrate film alters the voltammetry response for Fe(CN)63 −/4 −.

The evolution of electrochemical characteristics of a gold electrode upon the deposition of one and more atomic silver layers was studied by means of cyclic voltammetry and the method of potential temperature jump induced by the laser irradiation. Characteristics of the electric double layer on Ag monolayer are determined to be close to those of a massive silver electrode. Meanwhile, the electron-transfer parameters for the model redox system Fe(CN)63 −/4 − correspond to a gold electrode. The silver beyond the first atomic layer in multilayer deposits was shown to transform into Ag hexacyanoferrate (II) due to the spontaneous chemical reaction with K3Fe(CN)6 from the solution. For the Fe(CN)63 −/4 − redox system, the difference between oxidation and reduction peak potentials on a cyclic voltammogram increases with the growth of the silver layers number. This effect results from the corresponding increase in the ohmic resistance of the silver hexacyanoferrate (II) film and is not attributed to the changes in the electron-transfer kinetics.

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