Initial Stages of the Cathodic Corrosion of Au(111) in the Ionic Liquid [MPPip][TFSI] in Dependence of the Water Content: An in situ STM study

Many electrochemical processes, such as metal deposition and electrocatalytic reactions, occur at low potentials. Under these conditions, the electrode is considered stable against oxidation. However, noble metal surfaces can be restructured and dissolved by cathodic corrosion. A fundamental understanding of the underlying processes is necessary to control or prevent structural evolution. In this study, we show the initial stages of cathodic corrosion of a Au(111) surface in contact with the ionic liquid N-methyl-N-propylpiperidinium bis(trifluoromethane)sulfonimide ([MPPip] [TFSI]) in dependence on the water content. We show that the elbow sites of the herringbone-reconstructed surface are reactive sites for cathodic corrosion and that the corrosion rate increases with increasing water content.