Electrochemical potential

The electrochemical potential of the chemical potential of an ion in an electric potential.

Indicates how much work is to be applied to increase in a system at constant pressure, constant temperature and constant amounts of all of the other system components, the amount of ionic species from to.

( Under the conditions mentioned comparisons, the applied work is equal to the change in the Gibbs free energy of the system. Chemical potential. )

Since each potential difference describes a system's ability to do work, chemical reactions take place with the participation of ions until the electrochemical potentials of all system components have been adjusted. The consideration of the principle of phase boundaries, which are permeable for only one type of ion, explaining the operation of the glass electrode as a pH meter as well as the formation of the Donnan potential ( by Frederick George Donnan ) of biological membranes, and leads to the derivation of the Nernst equation.

The concept is not limited to ions, but can be applied to all electrically charged particles. For example, the Fermi energy of the electrons of a solid is equal to its electrochemical potential. The approximation of the electrochemical potentials of the electrons over the area of ​​contact between a metal and a semiconductor, resulting in the formation of a Schottky barrier, which is of importance in semiconductor technology.

The potential E of the electrode, although in electrochemistry particularly important potential and depends directly on the treated here electrochemical potential, but differs from the given here strict definition of the electrochemical potential E is an electrical voltage, that an energy per charge, the potential discussed here but an energy per mole