Double-layer structure of the Pt(111)–aqueous electrolyte interface

Abstract

Significance The Pt(111)–electrolyte interface is one of the most important model interfaces in physical electrochemistry. Here, we present detailed capacitance measurements of Pt(111) in contact with nonspecifically adsorbed electrolytes in combination with modeling to show that this interface does not follow classic Gouy–Chapman–Stern behavior. Our combined experimental-theoretical work suggests a picture of the double layer of Pt(111) with an increased ion concentration close to the interface as a consequence of a weak attractive ion–surface interaction and a changing polarizability of the Pt(111)–water interface due to the potential-dependent water adsorption and orientation.