Abstract
In the present communication, an attempt is made to demonstrate (once again) some of the problems with the derivation of the “generalized Lippmann equation” considered to be valid by many researchers for solid electrodes and to address the problems in the framework of the Gibbs model of the interface by using only the basic principles of thermodynamics. By surveying the relevant literature, it has been shown that during the derivation of the equation, it was completely ignored that the Gibbs-Duhem equation (i.e., the electrocapillary equation) is a mathematical consequence which follows directly from the homogeneous degree one property of the corresponding thermodynamic potential function; consequently, the resulting expression cannot be correct. Some alternative approaches have also been considered. The adequacy of the open system and the partly closed system approach has been critically discussed, together with the possibility of introducing new thermodynamic potential functions.
Highlights
The primary goals of all thermodynamic treatments are to describe heterogeneous systems with interfaces in terms of experimentally accessible quantities and to derive functions which enable one to relate and compare the thermodynamic properties of a system described by one set of physicochemical parameters to those corresponding to different thermodynamic states.The thermodynamic theory describing the properties of the electrified liquid/liquid interface is quite well developed
The internal energy of a thermodynamic system is determined by its state and not by processes. This brings us to our second point, namely, the thermodynamic potential functions introduced in the Gibbs or Guggenheim models to describe the thermodynamic properties of the interface are homogeneous functions of degree one with respect to its extensive variables, changes in the system (“processes”) in which the change of an extensive variable is not accompanied by a proportional increase in the number of moles of the surface atoms are allowed
In the model of Gibbs, the real interfacial region is replaced by a mathematical dividing surface, and the surface excess quantities are the respective differences between the real system and the chosen reference system
Summary
The primary goals of all thermodynamic treatments are to describe heterogeneous systems with interfaces in terms of experimentally accessible quantities and to derive functions which enable one to relate and compare the thermodynamic properties of a system described by one set of physicochemical parameters to those corresponding to different thermodynamic states. [24]) cannot, bear this name, since it contains differentials of the extensive parameter Ω This means that equations like Eq (6) are inconsistent with classical thermodynamics stating that the Gibbs-Duhem equation presents the relationship between the intensive variables in the differential form. It is emphasized again that in the Gibbs model, the interface is treated as a mathematical dividing plane between the two macroscopic phases, and its properties are given in terms of the surface excess values relative to a hypothetical reference system containing homogeneous phases in which the values of all intensive variables and associated properties are uniform and equal with those in the interface
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
