Open AccessEvaluating and Developing a Reliable Reference Electrode for Choline Chloride Based Deep Eutectic Solvents
Author(s) -
Xiaochen Shen,
Nicholas Sinclair,
Jesse S. Wainright,
Rohan Akolkar,
Robert F. Savinell
Publication year - 2020
Publication title -
journal of the electrochemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.258
H-Index - 271
eISSN - 1945-7111
pISSN - 0013-4651
DOI - 10.1149/1945-7111/ab913c
Subject(s) - choline chloride , eutectic system , electrochemistry , electrode , deep eutectic solvent , chloride , chemistry , redox , ionic liquid , standard electrode potential , inorganic chemistry , reference electrode , organic chemistry , alloy , catalysis
The Ag/AgCl reference electrode is commonly used in choline chloride based deep eutectic solvents. However, we found it undergoes significant potential shifts in electrochemical tests which previous reports largely ignored. In this work, we studied the degradation mechanism leading to its instability. Results show that due to the high Cl − concentration in ethaline, the AgCl film easily dissolves and forms AgCl 2 − species causing a potential shift. Therefore, we suggest a [Fe(CN) 6 ] 3− /[Fe(CN) 6 ] 4− reference electrode based on the reversibility and low diffusivity of [Fe(CN) 6 ] 3− /[Fe(CN) 6 ] 4− redox couple in ethaline, which was demonstrated to be reliable and stable over weeks of operation.