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 wo rk function, Phi (w), of the gas-exposed catalyst working electrode surface on catalyst potential V-WR, in solid state electrochemistry, i.e. e DeltaV (WR)=Delta Phi (W), the subject has attracted considerable attention and se veral laboratories have confirmed its validity. In a recent letter Williams and Aldao [Surf. Sci. 425 (1999) L387] have questioned the currently accep ted rationalization of the above experimental equation and have concluded t hat it cannot be rationalized or derived when the working electrode is grou nded. In this paper we summarize the experimental results and analyze the u nderlying electrochemical and surface science concepts to show that the abo ve 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 invest igations. (C) 2000 Elsevier Science B.V. All rights reserved.