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Spotlight on the Effect of Electrolyte Composition on the Potential of Maximum Entropy: Supporting Electrolytes Are Not Always Inert
Author(s) -
Ding Xing,
Garlyyev Batyr,
Watzele Sebastian A.,
Kobina Sarpey Theophilus,
Bandarenka Aliaksandr S.
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202101537
Subject(s) - electrolyte , inert , composition (language) , chemistry , chemical engineering , thermodynamics , physics , engineering , organic chemistry , electrode , philosophy , linguistics
The influence of electrolyte pH, the presence of alkali metal cations (Na + , K + ), and the presence of O 2 on the interfacial water structure of polycrystalline gold electrodes has been experimentally studied in detail. The potential of maximum entropy (PME) was determined by the laser‐induced current transient (LICT) technique. Our results demonstrate that increasing the electrolyte pH and introducing O 2 shift the PME to more positive potentials. Interestingly, the PME exhibits a higher sensitivity to the pH change in the presence of K + than Na + . Altering the pH of the K 2 SO 4 solution from 4 to 6 can cause a drastic shift in the PME. These findings reveal that, for example, K 2 SO 4 and Na 2 SO 4 cannot be considered as equal supporting electrolytes: it is not a viable assumption. This can likely be extrapolated to other common “inert” supporting electrolytes. Beyond this, knowledge about the near‐ideal electrolyte composition can be used to optimize electrochemical devices such as electrolyzers, fuel cells, batteries, and supercapacitors.