Using an electrode with renewable surface for study of silver reduction from acid thiourea solutions

Abstract

Sulfur-containing thiourea (TU) decomposition products exert a considerable effect on the silver electroreduction rate in TU solutions. The technique of removing a thin layer from a metal electrode in-situ at a fixed electrode potential makes it possible to minimize the influence of adsorbed impurities on the rate of the process under study. The values of the exchange current and transfer coefficient for silver reduction from TU solutions have been determined using this technique. Impurities in acid TU solution substantially increase the reduction rate for potentials more positive than about -0.5 V vs. Ag/AgCl.

High current density electrodeposition from silver complex ionic liquids

“…To improve the morphology of the deposited silver layers, the additives thiourea and 1H-benzotriazole were tested. Thiourea is known to act as a brightener and suppressor in aqueous silver plating, [57][58][59][60][61][62] while 1H-benzotriazole can adsorb on silver 63 and act as an accelerator. 57 These two additives were added to [Ag(MeCN are summarized in Table 2.…”

Anode current on gold in mixed thiosulfate-sulfite electrolytes

“…Cutting was performed directly in the solution under study. This procedure ensures rapid preparation of a "pure" and reproducible metal surface [11]. Voltammograms were measured using the following procedure.…”

RDE study of thiosulfate oxidation on gold

“…The electrode surface was renewed directly before measurement in the solution under study by cutting off a thin (%5 l) metal layer. This method of electrode surface preparation ensures the fresh and reproducible metal surface for each voltammogram [9].…”

“…The lateral interaction between adsorbed particles can lead to the formation of a broad range of various oxygen-containing sulfur species on the surface of gold electrode. For example, the formation of SAS bond between two adsorbed radicals can promote the formation of S 4 O 2À 6 ðadsÞ (reaction 8) and the rupture of AuAS bond, which causes its desorption (9) and gives tetrathionate ions in the solution volume. For visualization, these stages are shown schematically:…”