Measuring the potential at the counter electrode with VIONIC powered by INTELLO

Importance of the Topic

Electrochemical experiments often rely on precise potential control at multiple electrodes to fully understand reaction mechanisms. Monitoring the counter electrode potential alongside the working electrode potential prevents unwanted side reactions, such as platinum dissolution, which can bias analytical results. The ability to measure both potentials in real time enhances data reliability in electrocatalysis and other electrochemical applications.

Objectives and Study Overview

This application note demonstrates how to use the second sense channel (S2) of the VIONIC potentiostat/galvanostat, powered by INTELLO software, to simultaneously monitor the counter electrode potential during platinum oxidation in acidic media. Comparative analysis between working and counter electrode potentials highlights the importance of dual-sensing in complex electrochemical cells.

Methodology and Instrumentation

Experiments employed a Metrohm Autolab VIONIC instrument with INTELLO software, configured for a three-electrode cell with an added second sense lead:

• Working electrode: Platinum wire
• Counter electrode: Platinum sheet
• Reference electrode: Ag/AgCl in 3 M KCl
• Cell: Autolab RRDE cell inside a Faraday cage
• Measurement: Linear cyclic voltammetry (CV) with scan rate 500 mV/s, potential window 0.15 V → 1.35 V → –0.81 V → 0.15 V, 5 mV steps, 10 ms sampling

Key Results and Discussion

Cyclic voltammograms over three consecutive sweeps show consistent oxidation and reduction features on the working electrode. Time-domain plots reveal the counter electrode potential rising above 0.6 V during anodic scans. However, this value remains below thresholds for substantial platinum electrodissolution, indicating stable operation under the chosen conditions.

Benefits and Practical Applications

Dual-potential monitoring allows:

• Early detection of counter electrode overpotentials that may trigger unwanted dissolution;
• Enhanced accuracy in interpreting working electrode kinetics;
• Improved experimental design for electrocatalysis and corrosion studies.

Future Trends and Opportunities

Advancements in multi-channel potentiostats will enable more complex cell configurations, including four-electrode setups for localized impedance mapping. Integration with high-frequency electrochemical impedance spectroscopy (EIS) and faster sampling will further refine mechanistic insights. Applications may expand to in situ monitoring in energy storage devices and real-time quality control in industrial electrolytic processes.

Conclusion

The VIONIC potentiostat with INTELLO software effectively measures both working and counter electrode potentials, minimizing analytical bias from electrode dissolution. This capability supports robust electrocatalysis research and improves electrochemical cell diagnostics.

References

1. L. Xing et al., Electrocatalysis, 5 (2014) 96–112.