Changes in the polycrystalline gold electrode surface produced by square wave potential perturbations

Abstract

The electroreduction of gold oxide layers produced by a square wave potential signal (SWPS) under a proper set of perturbation conditions yields a reproducible electrode surface with a large increase in the surface area. The different variables are systematically investigated to establish the optimal conditions of the SWPS. The results are discussed on the basis of the thermodynamics and kinetics of oxide monolayer and multilayer formation .

The mechanism of oxygen evolution at superactivated gold electrodes in aqueous alkaline solution

“…0.85 V. Moreover, the overall C2 reduction process extends over a wide potential range from ca. 0.9 to 0 V versus RHE, in agreement with the observations of Burke and coworkers [56][57][58][59][60]. The latter authors propose that these peaks and the extensive tailing could reflect the presence of slightly different forms of the hydrated oxide due to variations in density, degree of hydration and crystallinity, among others [31,32], and have noted that at least three distinct forms of the Au ß-oxide exist [62].…”

“…This feature, labelled C2, can be attributed to the reduction of a multilayer hydrous ß-oxide which formed on the electrode surface during the series of oxygen evolution polarisation experiments. It is well established that multilayer hydrous oxide deposits can be readily produced on Au in aqueous solution using a range of methods [56][57][58], including dc polarisation in the oxygen evolution region [56][57][58]. Indeed, the progressive thickening of the oxide layer is evident from the significant increase in the oxide reduction charge capacity of the used electrode; the total charge under the C1 peak in Fig.…”

“…For thin films, the reduction of the hydrous oxide deposit on Au gives rise to a single peak at ca. 0.6 V versus RHE [56][57][58]. However, with thicker films, multiple peaks or shoulders superimposed on an extensive reduction tail have been noted [56][57][58][59][60].…”

Nanoporous Gold Surface: An Efficient Platform for Hydrogen Evolution Reaction at Very Low Overpotential

“…27,28 Hence, it is really a challenging task to develop convenient and green methods to fabricate NPGF with high surface area. Gold surfaces with such features have been produced by square wave potential perturbations, 29 anodization in oxalate solution, 30 anodization of gold in HCl medium, 31 dealloying of silver/gold alloys, 32 anodization using ascorbic acid as reducing agents 33 and electroless deposition of iridium oxide nanoparticles on an anodized gold surface. 34 Also, gold nanomaterials have been found to be catalytically active and relatively stable in acid medium.…”

Cathodic re-activation of the gold electrode in pulsed electrochemical detection of carbohydrates

“…Numerous studies on electrochemical behavior of gold have been carried out for decades [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] and some of them also in order to perform PAD waveform optimization for IC detection. Gold metal was considered as poor catalyst for many electrochemical reactions due to the weak chemisorption properties.…”