Anion Layering and Steric Hydration Repulsion on Positively Charged Surfaces in Aqueous Electrolytes
Journal
CHEMPHYSCHEM
Journal Volume
18
Journal Issue
21
Pages
3056-3065
Date Issued
2017
Author(s)
Abstract
) in pure acids at pH ?1, where protons are the co-ions. Solutions containing anions with low hydration energies exhibit repulsive structural hydration forces, indicating significant ion and/or water structuring within the first 1-2 nm on a positively charged surface. We attribute this to specific adsorption effects within the Stern layer. In contrast, ions with high hydration energies show exponentially repulsive hydration forces, indicating a lower degree of structuring within the Stern layer. The presented data demonstrates that anion hydration forces in the inner double layer are comparable to cation hydration forces, and that they qualitatively correlate with hydration free energies. This work contributes to understanding interaction processes in which positive charge is screened by anions within an electrolyte.
SDGs
Type
journal article