Coulombic Surface-Ion Interactions Induce Nonlinear and Chemistry-Specific Charging Kinetics

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Abstract

While important for many industrial applications, chemical reactions responsible for the charging of solids in water are often poorly understood. We theoretically investigate the charging kinetics of solid-liquid interfaces and find that the time-dependent equilibration of surface charge contains key information not only on the reaction mechanism, but also on the valency of the reacting ions. We construct a nonlinear differential equation describing surface charging by combining chemical Langmuir kinetics and electrostatic Poisson-Boltzmann theory. Our results reveal a clear distinction between late-time (near-equilibrium) and short-time (far-from-equilibrium) relaxation rates, the ratio of which contains information on the charge valency and ad- or desorption mechanism of the charging process. Similarly, we find that single-ion reactions can be distinguished from two-ion reactions, as the latter show an inflection point during equilibration. Interestingly, such inflection points are characteristic of autocatalytic reactions, and we conclude that the Coulombic ion-surface interaction is an autocatalytic feedback mechanism.

Original languageEnglish
Article number058001
Number of pages6
JournalPhysical Review Letters
Volume130
Issue number5
DOIs
Publication statusPublished - 3 Feb 2023

Bibliographical note

Funding Information:
We thank Ben Werkhoven and Cheng Lian for fruitful discussion, and an anonymous referee for pointing us to the pressure-jump experiments in Refs. . This work is part of the D-ITP consortium, a program of the Netherlands Organisation for Scientific Research (NWO) that is funded by the Dutch Ministry of Education, Culture and Science (OCW).

Publisher Copyright:
© 2023 American Physical Society.

Funding

We thank Ben Werkhoven and Cheng Lian for fruitful discussion, and an anonymous referee for pointing us to the pressure-jump experiments in Refs. . This work is part of the D-ITP consortium, a program of the Netherlands Organisation for Scientific Research (NWO) that is funded by the Dutch Ministry of Education, Culture and Science (OCW).

Keywords

  • Chemical kinetics dynamics & catalysis
  • Chemical reactions
  • Charged colloids
  • Liquid-solid interfaces
  • Polymers & Soft Matter
  • Statistical Physics
  • Nonlinear Dynamics

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