A study on the voltammetric behaviour of silver on electrodispersed platinum electrodes in acid solution

Abstract

The early stages of Ag electrodeposition on columnar structured Pt electrodes was investigated in acid solutions covering the underpotential deposition (upd) and overpotential deposition (opd) ranges. Results show a remarkable dependence of the Ag growth mode on the electrode roughness and potential sweep rate. At high potential sweep rates and large substrate roughness factors a 3-D to 2-D rearrangement can be detected. This process appears to be also accompanied by a Pt-Ag formation. For this type of electrode, both processes hinder the nucleation and growth of the 3-D Ag phase. Under certain conditions the complete Ag plating of the entire porous structure can be produced and the voltammetric behaviour of the system then approaches that observed for the Ag/Ag+ electrode reaction at an electrochemical thin layer cell.

The electrodeposition of mercury from aqueous Hg22+ ion-containing acid solutions on smooth and columnar-structured platinum electrodes

“…The preparation technique for cs-Pt electrodes was the same as that described elsewhere [27,28]. As has been concluded from scanning tunneling microscopy (STM) [29,30], ellipsometry [31], ultraviolet and visible electroreflectance spectroscopy [32], and electrochemical data [20,21,23,25,[33][34][35][36][37], the columnar microstructure of cs-Pt consists of an average column height in the range 10-10,000 nm, a void-to-filled volume ratio of about 0.5, and columns and intercolumnar voids about 10 nm in average diameter (Fig. 2).…”

“…Each cs-Pt electrode behaves as a rough polycrystalline Pt electrode with an almost constant distribution of crystallographic orientations, regardless of the magnitude of the roughness factor (R), at least in the range 1 E R E 10 3 [26,27]. These electrodes attain a stable value of R after being immersed in aqueous 1 M H2SO4 for 24 h [20,21,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37]. The value of R was defined as the (QH)R/(QH)I ratio, where (QH)R and (QH)I are the H-atom electrodesorption voltammetric charge for cs-Pt and smooth pc-Pt electrodes, respectively, both measured in aqueous 1 M H2SO4 under the same voltammetric conditions [26,38].…”

Spontaneous Deposition of Ag. Influence of Composition of Ag-Containing Solution on the Electrocatalytic Activity of Pt-Modified Surface

“…Other researchers have focused the experiments on the characterization of Ag spontaneous deposits formed on single crystal Pt surfaces [12][13][14] and in dissolutions containing sulfate and perchlorate ions [15][16][17][18]. For this purpose, Palacio et al applying X-ray photoelectron spectroscopy and X-ray photoelectron spectroscopy with angular resolution techniques determined the chemical composition of Ag deposits on Pt surfaces [19].…”

The Effects of Organic Adsorbates on the Underpotential and Bulk Deposition of Silver on Polycrystalline Platinum Electrodes

“…The electrodeposition of silver onto polycrystalline platinum electrodes has been the subject of numerous investigations [1][2][3][4][5][6][7][8]. Initial studies by Cadle and Bruckenstein [11 characterized the inhibitive effects of silver deposition on the adsorption of hydrogen and they determined that an amount equivalent to 1.4 monolayers was necessary to completely block the surface.…”

“…Scharifker has investigated the possibility of alloy formation [5], and Arvia has proposed the existence of energetically distinct silver layers deposited at underpotentials [6][7][8].…”