A Model Electron Transfer Reaction in Confined Aqueous Solution

Liquid water confined within nanometer-sized channels exhibits a strongly reduced local dielectric constant perpendicular to the wall, especially at the interface, and this has been suggested to induce faster electron transfer kinetics at the interface than in the bulk. We study a model electron transfer reaction in aqueous solution confined between graphene sheets with classical molecular dynamics. We show that the solvent reorganization energy is reduced at the interface compared to the bulk, which explains the larger rate constant. However, this facilitated solvent reorganization is due to the partial desolvation by the graphene sheet of the ions involved in the electron transfer and not to a local dielectric constant reduction effect.

Automated summary

The study found that electron transfer reactions in aqueous solutions confined between graphene sheets can occur faster than in bulk due to a reduction in solvent reorganization energy at the interface. However, this reduction is attributed to the partial desolvation of ions involved in the electron transfer by the graphene sheet, rather than a reduction in local dielectric constant.