The

Abstract

A new concept for an “all solid state” reference half-cell for use in aqueous solutions based on mixed valent transition metal oxids is presented. XPS-surface analytical measurements demonstrate the adaptation of the surface chemistry to the chemistry of the solution ("Chameleon Surface"). Thus the driving force of the potential formation at the solid/liquid interface is significantly attenuated which may explain the electrochemically observed sub-Nernst sensitivities (~ 10 mV/pH).