Epm. Leiva, THERMODYNAMIC DERIVATION AND MODEL-CALCULATIONS OF THE METAL UNDERPOTENTIAL DEPENDENCE ON ELECTRON WORK FUNCTION DIFFERENCES, Journal of electroanalytical chemistry [1992], 350(1-2), 1993, pp. 1-14
The relationship between the work function of the substrate + adsorbat
e system and the underpotential shift is derived from a thermodynamic
argument. An alternative explanation of the correlation formulated in
the literature between the underpotential shift and the work function
difference of the metals involved is proposed. A simple model is used
to illustrate the meaning of the equations derived. Abrupt adsorption-
desorption behaviour is predicted for those electrochemical systems wh
ere the work function shows a pronounced minimum as a function of the
coverage, provided that this is a first-order contribution to the chem
ical potential of the system.