Editing Desorption (section)

=== Reductive or oxidative desorption ===
In some cases, the adsorbed molecule is chemically bonded to the surface/material, providing a strong adhesion and limiting desorption. If this is the case, desorption requires a chemical reaction which cleaves the [[chemical bond]]s. One way to accomplish this is to apply a voltage to the surface, resulting in either reduction or oxidation of the adsorbed molecule (depending on the bias and the adsorbed molecules).

In a typical example of reductive desorption, a [[self-assembled monolayer]] of [[thiol|alkyl thiols]] on a [[gold]] surface can be removed by applying a negative bias to the surface resulting in reduction of the sulfur head-group. The chemical reaction for this process would be:

: <math>R - S - Au + e^- \longrightarrow R - S^- + Au </math>

where R is an alkyl chain (e.g. CH<sub>3</sub>), S is the sulfur atom of the thiol group, Au is a gold surface atom and e<sup>−</sup> is an electron supplied by an external voltage source.<ref>Sun, K., Jiang, B., & Jiang, X. (2011). Electrochemical desorption of self-assembled monolayers and its applications in surface chemistry and cell biology. ''Journal of Electroanalytical Chemistry'', ''656''(1), 223-230.</ref>

Another application for reductive/oxidative desorption is to clean active carbon material through [[electrochemical regeneration]].