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.