Fundamentals and Implication of Point of Zero Charge (PZC) Determination for Activated Carbons in Aqueous Electrolytes

Fundamentals and Implication of Point of Zero Charge (PZC) Determination for Activated Carbons in Aqueous Electrolytes

Abstract The point of zero charge (PZC) is a crucial parameter for investigating the charge storage mechanisms in energy storage systems at the molecular level. This paper presents findings from three different electrochemical techniques, compared for the first time: cyclic voltammetry (CV), stairca...

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Bibliographic Details
Main Authors: Sylwia Slesinska, Przemysław Galek, Jakub Menzel, Scott W. Donne, Krzysztof Fic, Anetta Płatek‐Mielczarek
Format: Article
Language:English
Published: Wiley 2024-12-01
Series:Advanced Science
Subjects:
activated carbon (AC)
aqueous electrolyte
electrochemical capacitor (EC)
electrochemical quartz crystal microbalance (EQCM)
point of zero charge (PZC)
Online Access:https://doi.org/10.1002/advs.202409162
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Summary:Abstract The point of zero charge (PZC) is a crucial parameter for investigating the charge storage mechanisms in energy storage systems at the molecular level. This paper presents findings from three different electrochemical techniques, compared for the first time: cyclic voltammetry (CV), staircase potentio electrochemical impedance spectroscopy (SPEIS), and step potential electrochemical spectroscopy (SPECS), for two activated carbons (ACs) with 0.1 mol L−1 aqueous solution of LiNO3, Li2SO4, and KI. The charging process of AC operating in aqueous electrolytes appears as a complex phenomenon – all ionic species take an active part in electric double‐layer formation and the ion‐mixing zone covers a wide potential region. Therefore, the so‐called PZC should not be considered as an absolute one‐point potential value, but rather as a range of zero charge (RZC). SPECS technique is found to be a universal and fast method for determining RZC, as applied here together with the EQCM. In most cases, the RZC covers a potential range from ≈100 to ≈200 mV and the correlation of the range with the carbon microtexture is clear, highlighting the role of the ion‐sieving effect. It is postulated that PZC for porous materials in aqueous electrolytic solutions should be considered instead as RZC.
ISSN:2198-3844

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