Extended Nernst–Planck Equation Incorporating Partial Dehydration EffectSupported by the National Natural Science Foundation of China (Grant No. 11875076).

Abstract

Novel ionic transporting phenomena emerge as nanostructures approach the molecular scale. At the sub-2nm scale, widely used continuum equations, such as the Nernst–Planck equation, break down. Here, we extend the Nernst–Planck equation by adding a partial dehydration effect. Our model agrees with the reported ion fluxes through graphene oxide laminates with sub-2nm interlayer spacing, outperforming previous models. We also predict that the selectivity sequences of alkali metal ions depend on the geometries of the nanostructures. Our model opens a new avenue for the investigation of the underlying mechanisms in nanofluidics at the sub-2nm scale.