On the work function of the gas-exposed electrode surfaces in solid state electrolyte cells

Since the first experimental reports on the one-to-one dependence of the work function, ΦW, of the gas-exposed catalyst working electrode surface on catalyst potential VWR in solid state electrochemistry, i.e.eΔVWR=ΔΦWthe subject has attracted considerable attention and several laboratories have confirmed its validity. In a recent letter Williams and Aldao [Surf. Sci. 425 (1999) L387] have questioned the currently accepted rationalization of the above experimental equation and have concluded that it cannot be rationalized or derived when the working electrode is grounded. In this paper we summarize the experimental results and analyze the underlying electrochemical and surface science concepts to show that the above equation, involving thermodynamic properties, does not depend on which, if any, electrode is grounded. The physical origin and limitations of this equation are also discussed in light of recent surface spectroscopic investigations.