Operando impedance spectroscopy informed dynamic internal resistance compensation mitigates bubble-induced distortions of the applied potential

Tomc, Blaž (author), Hotko, Miha (author), Marsel, Aleš (author), Maselj, Nik (author), Svete, Maja (author), Suhadolnik, Luka (author), Bele, Marjan (author), Farinazzo Bergamo Dias Martins, Pedro (author), Strmčnik, Dušan (author), Gaberšček, Miran (author), Hodnik, Nejc (author)

Bubble formation during gas-evolving electrochemical reactions disrupts potential control and obscures intrinsic catalyst−performance relationships. While conventional strategies to mitigate this issue have relied on surface engineering or cell design, here we introduce a dynamic internal resistance (IR) compensation approach that adapts to bubble-induced fluctuations in real time. This was achieved by employing (i) operando electrochemical impedance spectroscopy (EIS), which provided the electrolyte resistance (R$_{Ohm}$) parameter continuously, and (ii) a Python control loop to extract EIS data and dynamically adjust the IR compensation. This self-correcting approach effectively suppressed bubble-induced artifacts during prolonged electrochemical CO$_2$ reduction (ECO$_2$R) on copper, enabling accurate performance evaluation and reliable assessment of catalyst instability under realistic operating conditions. We argue that such control is essential in ECO$_2$R stability studies, where even minor potential shifts can obscure intrinsic catalyst−performance relationships and hinder mechanistic insight into degradation.

• Language: English
• Keywords: electrochemical impedance spectroscopy, operando EIS, IR compensation, bubbles, stability, electrochemical CO$_2$ reduction, catalysts, copper, redox reactions, selectivity
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: Str. 2823–2830
• Numbering: Vol. 1, iss. 12
• PID: 20.500.12556/RUL-176942
• UDC: 66
• ISSN on article: 2997-0571
• DOI: 10.1021/acselectrochem.5c00368
• COBISS.SI-ID: 261429251
• Publication date in RUL: 16.12.2025

Record is a part of a journal

• Title: ACS electrochemistry
• Shortened title: ACS electrochem.
• Publisher: American Chemical Society
• ISSN: 2997-0571
• COBISS.SI-ID: 252727299

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: kemijska tehnologija, elektrokemija, katalizatorji, spektroskopija