Issue 24, 2023

Probing collective terahertz vibrations of a hydrogen-bonded water network at buried electrochemical interfaces

Abstract

The exceptional properties of liquid water such as thermodynamic, physical, and dielectric anomalies originate mostly from the hydrogen-bond networks of water molecules. The structural and dynamic properties of the hydrogen-bond networks have a significant impact on many biological and chemical processes in aqueous systems. In particular, the properties of interfacial water molecules with termination of the network at a solid surface are crucial to understanding the role of water in heterogeneous reactions. However, direct monitoring of the dynamics of hydrogen-bonded interfacial water molecules has been limited because of the lack of a suitable surface-selective spectroscopic means in the terahertz (THz) frequency range where collective vibrations of water exist. Here we show that hydrogen-bond vibrations below 9 THz can be measured in situ at an electrochemical interface, which is buried between two THz-opaque media, by using a density of states format of surface-enhanced inelastic light scattering spectra. The interpretation of the obtained spectra over the range 0.3–6 THz indicates that the negatively charged surface accelerates collective translational motions of water molecules in the lateral direction with the increase of hydrogen-bond defects. Alternatively, the positively charged surface results in suppression of lateral mobility. This work gives a new perspective on in situ spectroscopic investigations in heterogeneous reactions.

Graphical abstract: Probing collective terahertz vibrations of a hydrogen-bonded water network at buried electrochemical interfaces

Supplementary files

Article information

Article type
Edge Article
Submitted
04 apr 2023
Accepted
13 maj 2023
First published
15 maj 2023
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2023,14, 6531-6537

Probing collective terahertz vibrations of a hydrogen-bonded water network at buried electrochemical interfaces

T. Isogai, M. Uranagase, K. Motobayashi, S. Ogata and K. Ikeda, Chem. Sci., 2023, 14, 6531 DOI: 10.1039/D3SC01734F

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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