Probing Electrified Liquid-Solid Interfaces with Scanning Electron Microscopy

Hongxuan Guo; Alexander Yulaev; Evgheni Strelcov; Alexander Tselev; Christopher Arble; Andras E Vladar; John S Villarrubia; Andrei Kolmakov

doi:10.1021/acsami.0c19634

Probing Electrified Liquid-Solid Interfaces with Scanning Electron Microscopy

ACS Appl Mater Interfaces. 2020 Dec 16;12(50):56650-56657. doi: 10.1021/acsami.0c19634. Epub 2020 Dec 2.

Authors

Hongxuan Guo^{1

2

3}, Alexander Yulaev^{2

3}, Evgheni Strelcov^{2

3}, Alexander Tselev⁴, Christopher Arble², Andras E Vladar², John S Villarrubia², Andrei Kolmakov²

Affiliations

¹ SEU-FEI Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education, Southeast University, Nanjing 210096, P. R. China.
² Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States.
³ Maryland Nanocenter, University of Maryland, College Park, Maryland 20742, United States.
⁴ Department of Physics and CICECO-Aveiro Institute of Materials, University of Aveiro, Aveiro 3810-193, Portugal.

PMID: 33327058
DOI: 10.1021/acsami.0c19634

Abstract

Electrical double layers play a key role in a variety of electrochemical systems. The mean free path of secondary electrons in aqueous solutions is on the order of a nanometer, making them suitable for probing ultrathin electrical double layers at solid-liquid electrolyte interfaces. Employing graphene as an electron-transparent electrode in a two-electrode electrochemical system, we show that the secondary electron yield of the graphene-liquid interface depends on the ionic strength and concentration of the electrolyte and the applied bias at the remote counter electrode. These observations have been related to polarization-induced changes in the potential distribution within the electrical double layer and demonstrate the feasibility of using scanning electron microscopy to examine and map electrified liquid-solid interfaces.

Keywords: electrical double layer; electrified interfaces; electrochemistry; electrolyte; graphene electrode; liquid cell; polarization; scanning electron microscopy; secondary electron emission.