heterogeneous diffusion rate constant

in electrochemistry
https://doi.org/10.1351/goldbook.H02805
Defined by the equation: $k_{\text{d}}=\frac{I_{\text{l}}}{n\ F\ c\ A}$ where the @[email protected] $$I_{\text{l}}$$ is assumed to be due to the @[email protected] species of concentration $$c$$ and of @[email protected] $$D$$. $$n$$ is the @[email protected] written so that the @[email protected] @[email protected] of this species is unity. $$A$$ is usually taken as the geometric area of the electrode, and $$F$$ is the @[email protected]
Source:
PAC, 1974, 37, 499. (Electrochemical nomenclature) on page 513 [Terms] [Paper]