The current testing of the electrochemical active surface area (ECSA) of electrocatalysts is mainly conducted through CV scans at different rates. At the interface between the catalyst and the electrolyte, such as for semiconductor materials in a 1 M KOH electrolyte, a Mott-Schottky capacitance will be generated at the interface. Then, does the Mott-Schottky effect at the interface bring additional contributions to the results of CV tests, thereby affecting the accurate determination of ECSA? If so, how can ECSA be accurately obtained?
Dear friend Ji J Lee
Thank you for raising such a thought-provoking question regarding the complexities of electrochemical capacitance measurements. The interplay between double-layer capacitance and the Mott-Schottky effect indeed presents a nuanced challenge, especially when interpreting data from cyclic voltammetry (CV) scans.
As you noted, double-layer capacitance is often described by the Helmholtz model, where factors like electrode surface area and electrolyte properties are key. When using CV to estimate the electrochemically active surface area (ECSA), isolating the double-layer contribution becomes essential. However, the presence of a depletion layer at the semiconductor-electrolyte interface—manifested as Mott-Schottky capacitance—can complicate this analysis by introducing an additional, frequency-dependent component.
To address this, have you considered employing electrochemical impedance spectroscopy (EIS) or varying the frequency of your capacitance measurements? Since double-layer and Mott-Schottky capacitances respond differently to frequency, such approaches could help disentangle their respective contributions. Additionally, applying mathematical models to your data may further clarify the distinct roles each capacitance plays.
I’d be very interested to hear your thoughts on these strategies, or if you’ve explored alternative methods. Please let me know if you’d like to discuss this further or need any resources—happy to help however I can.
An important article to read/cite:
Article Hierarchical Ni-Mn Double Layered/Graphene Oxide with Excell...
Best regards,
Kaushik
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