Reduction Potential

Definition

Reduction potential is a measure of a species’ tendency to gain electrons, used to compare the anodic and cathodic roles in a corrosion cell. Lower reduction potential favors oxidation, higher favors reduction.

The anode is the lower-reduction-potential site of oxidation while the cathode is the higher-reduction-potential site of reduction. Oxygen’s favorable reduction thermodynamics and high electronegativity make it an exceptionally strong electron sink that drives metal dissolution. Exposed bare metal has a much lower reduction potential than a surrounding passivated surface, which raises the voltage driving localized attack.

Related concepts

Galvanic Series · Voltage as Electromotive Force · Nobility

---

Part of The Blueprint of Water · ⚡ electrochemistry