Electrochemical formation and reduction of silver oxides in alkaline media

Abstract

The anodic oxidation of silver electrodes in NaOH solution and the reduction of the silver oxides formed were studied by potential step chronoamperometry. Oxidation of Ag to Ag20 is a diffusion-controlled reaction, the diffusion control being established in the solid phase. Oxidation of Ag20 to AgO proceeds via a nucleation and growth-controlled process. The amount of AgO decreased with increasing step height. The current--time curves for this reaction have been analysed with the Kolmogoroff--Avrami equation. Reduction of AgO to Ag20 occurs initially on the outside of the electrode, and the rate of the reaction is limited by diffusion of ions across the thickening layer of Ag20. Reduction of Ag20 to Ag proceeds via a nucleation and growth reaction.

Anodic silver (II) oxides investigated by combined electrochemistry, ex situ XPS and in situ X‐ray absorption spectroscopy

“…[14,15] The mechanism and the kinetics of Ag(I)-to Ag(II)-oxide formation as well as the morphology of the grown Ag(II) deposits were recently investigated in detail, and the results show that silver(II) oxide formation proceeds via nucleation, 3D growth and Ostwald ripening processes, [16] which was confirmed by previous studies based mainly on electrochemical experiments (e.g. refs [1,17]). Although there is general agreement about the formation of primary and secondary Ag(I) oxides and AgO with increasing oxidation potential, there is still a lack of detailed structural information during the different growth stages of the anodic oxides.…”

“…In most of the cases, the silver electrodes were then preoxidized at a potential of +0.7 V(SHE) for 600 s. Under these electrochemical conditions, a thick, crystalline Ag 2 O film was formed, [1,2,7,8] and the AgO formation was subsequently initiated by a second potential step to more anodic potentials. Finally, the samples were removed from the solution under potential control and rinsed with distilled water to remove any remaining electrolyte.…”

“…In general, two major anodic (a 1 , a 2 ) and two cathodic peaks (c 1 , c 2 ) related to the formation and the reduction of Ag 2 O and AgO are detectable in the cyclic voltammagram (e.g. refs [1,2], see also the inset of Fig. 1(a)).…”

Вольтамперометрическое Определение Пероксида Водорода C Помощью Сенсоров На Основе Наночастиц Серебра В Объектах Техногенного И Геологического Происхождения

“…Согласно литературным данным [28,29], два небольших максимума (А 1 , А 2 ) на анодных ветвях циклических зависимостей 1'-3′ соответствуют процессам окисления серебра из состава наночастиц. Схемы реакций их окисления (1), (2) согласуются с [27,[29][30][31]:…”

Optimization of Response of the Silver Oxide Electrode for the Detection of Carbohydrates and Related Compounds

“…However, in the cathodic scan, there is an anodic peak at about 450 mV, which is attributed to the further oxidation of silver(I). Droog and Huisman concluded that the formation of Ag 2 O occurs by a diffusion process while the formation of AgO occurs by a nucleation and growth process [17]. Once nucleation has occurred, further oxidation can proceed at a lower potential.…”