Electrode-Solution Interface: Distribution of Ions around an Electrode
What happens if a bar of a noble metal is immersed in an electrolyte solution such as ? Due to the difference between the electric potential of the metal and the electrode-solution interface, the ions will move to equalize the total charge. This Demonstration shows the distribution of ions (cation and anion ) near an electrode surface and also the variation of potential with distance from the electrode, as functions of concentration.
The distribution of ions is based on the Gouy–Chapman theory. The concentration profiles of and are colored blue and red, respectively. The electrode is positioned at . The filled part on the potential diagram represents the Debye length (a characteristic distance at which significant charge separation can occur). The red and blue points represent and ions, respectively.