Salt Solutions in Carbon Nanotubes: The Role of Cation-π Interactions

Tuan Anh Pham, S. M Golam Mortuza, Brandon C. Wood, Edmond Y Lau, Tadashi Ogitsu, Steven F. Buchsbaum, Zuzanna S. Siwy, Francesco Fornasiero, Eric Schwegler

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Understanding the structure of aqueous electrolytes at interfaces is essential for predicting and optimizing device performance for a wide variety of emerging energy and environmental technologies. In this work, we investigate the structure of two common salt solutions, NaCl and KCl, at a hydrophobic interface within narrow carbon nanotubes (CNTs). Using a combination of first-principles and classical molecular dynamics simulations in conjunction with molecular orbital analysis, we find that the solvation structure of the cations in the CNTs can deviate substantially from the conventional weakly interacting hydrophobic picture. Instead, interactions between solvated ions and π orbitals of the CNTs are found to play a critically important role. Specifically, the ion solvation structure is ultimately determined by a complex interplay between cation-π interactions and the intrinsic flexibility of the solvation shell. In the case of K+, these effects result in an unusually strong propensity to partially desolvate and reside closer to the carbon wall than both Na+ and Cl-, in sharp contrast with the known ion ordering at the water-vapor interface. (Graph Presented).

Original languageEnglish (US)
Pages (from-to)7332-7338
Number of pages7
JournalJournal of Physical Chemistry C
Volume120
Issue number13
DOIs
StatePublished - Apr 7 2016
Externally publishedYes

Fingerprint

Carbon Nanotubes
Solvation
solvation
Cations
Carbon nanotubes
Salts
Positive ions
carbon nanotubes
Ions
salts
cations
Environmental technology
energy technology
ions
Steam
interactions
Molecular orbitals
Water vapor
Electrolytes
water vapor

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Energy(all)

Cite this

Pham, T. A., Mortuza, S. M. G., Wood, B. C., Lau, E. Y., Ogitsu, T., Buchsbaum, S. F., ... Schwegler, E. (2016). Salt Solutions in Carbon Nanotubes: The Role of Cation-π Interactions. Journal of Physical Chemistry C, 120(13), 7332-7338. https://doi.org/10.1021/acs.jpcc.5b12245

Salt Solutions in Carbon Nanotubes : The Role of Cation-π Interactions. / Pham, Tuan Anh; Mortuza, S. M Golam; Wood, Brandon C.; Lau, Edmond Y; Ogitsu, Tadashi; Buchsbaum, Steven F.; Siwy, Zuzanna S.; Fornasiero, Francesco; Schwegler, Eric.

In: Journal of Physical Chemistry C, Vol. 120, No. 13, 07.04.2016, p. 7332-7338.

Research output: Contribution to journalArticle

Pham, TA, Mortuza, SMG, Wood, BC, Lau, EY, Ogitsu, T, Buchsbaum, SF, Siwy, ZS, Fornasiero, F & Schwegler, E 2016, 'Salt Solutions in Carbon Nanotubes: The Role of Cation-π Interactions', Journal of Physical Chemistry C, vol. 120, no. 13, pp. 7332-7338. https://doi.org/10.1021/acs.jpcc.5b12245
Pham, Tuan Anh ; Mortuza, S. M Golam ; Wood, Brandon C. ; Lau, Edmond Y ; Ogitsu, Tadashi ; Buchsbaum, Steven F. ; Siwy, Zuzanna S. ; Fornasiero, Francesco ; Schwegler, Eric. / Salt Solutions in Carbon Nanotubes : The Role of Cation-π Interactions. In: Journal of Physical Chemistry C. 2016 ; Vol. 120, No. 13. pp. 7332-7338.
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