We continue our investigation of the behavior of simple ions at aqueous interfaces, employing the combination of two surface-sensitive nonlinear spectroscopy tools, broadband deep UV electronic sum-frequency generation and UV second harmonic generation, to characterize the adsorption of thiocyanate to the interface of water with toluene─a prototypical hydrophobe. We find that both the interfacial spectrum and the Gibbs free energy of adsorption closely match results previously reported for the air-water interface. We observe no relative spectral shift in the higher-energy CTTS transition of thiocyanate, implying similar solvation environments for the two interfaces. Similarly, the Gibbs free energies of adsorption agree within error; however, we expect the respective enthalpic and entropic contributions to differ between the two interfaces, similar to our earlier findings for the air-water versus graphene-water interfaces. Further experiments and theoretical modeling are necessary to quantify the mechanistic differences.
|Original language||English (US)|
|Number of pages||7|
|Journal||Journal of Physical Chemistry Letters|
|State||Published - Dec 30 2021|
Bibliographical noteKAUST Repository Item: Exported on 2022-05-25
Acknowledged KAUST grant number(s): OSR-2019-CPF-4109.3
Acknowledgements: This work was supported by the Department of Energy, Office of Basic Energy Sciences, through the Chemical Sciences Division at the Lawrence Berkeley National Laboratory under contract #CH403503, through King Abdullah University of Science and Technology (KAUST) under contract #OSR-2019-CPF-4109.3, and through the ACS Petroleum Research Fund under grant #59408-ND6
This publication acknowledges KAUST support, but has no KAUST affiliated authors.
ASJC Scopus subject areas
- Materials Science(all)