Cyclic Voltammetry on Ag(111) and Ag(100) Faces in Sodium Hydroxide Solutions
B M. Jovic, V D. Jovic, Gery R. Stafford
The electrochemical behavior of silver (100) and (111) single crystal surfaces was examined in aqueous NaOH solution. The first step of silver oxidation is the electrosorption of OH- ions followed by phase transformation into a monolayer. The difference in peak potentials recorded in 0.1 mol dm-3 and 0.01 mol dm-3 NaOH solution of about 60 mV indicates that one electron is exchanged in the overall electrosorption reaction, implying a complete charge transfer between OH- ions and the silver surface. The electrosorption process was 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 due to roughening of the silver surface due to the formation and reduction of the oxide.