Cyclic voltammetry on Ag(111) and Ag(100) faces in sodium hydroxide solutions

The electrochemical behavior of silver (100) and (111) single crystal surfaces was examined by cyclic voltammetry in aqueous NaOH solution. In the 'double layer' region (between - 1.2 and 0.1 V (SCE)) adsorption of OH- ions followed by phase transformation into an Ag-OH monolayer was found to take place, The difference in peak potentials recorded in 0.1 and 0.01 mol dm(-3) NaOH solutions of about 60 mV indicate that one electron is exchanged in the overall electrochemical reaction, implying a complete charge transfer between OH- ions and the silver surface. The adsorption process has been modeled to a Frumkin adsorption isotherm. Further oxidation of silver into Ag2O takes place at more positive potentials. The formation of bulk Ag2O results in considerable change to the original single crystal surface. This is likely to bt: due to roughening of the silver surface as a consequence of the formation and reduction of the oxide. (C) 1999 Elsevier Science S.A. All rights reserved.