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Thin-Layer Electrochemistry: Visualizing the Diffusion Layer During Chronoamperometry and Cyclic Voltammetry
Mohammad Rafiee1, Lida Khalafi2, Keya Pandey1
1Division of Energy, Matter and Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, Missouri 64110, United States.
Journal of Chemical Education
|August 14, 2026
Summary
This study visualizes electrochemical diffusion layers using methyl viologen. The activity enhances student understanding of chronoamperometry and cyclic voltammetry by linking visual cues to electrochemical data.
Area of Science:
- Electrochemistry
- Chemical Education
Background:
- Diffusion layer phenomena are crucial in electrochemistry but difficult for students to grasp.
- Visualizing these processes aids comprehension.
Purpose of the Study:
- To develop a hands-on activity for observing diffusion layer changes during electrochemical experiments.
- To improve student understanding of chronoamperometry and cyclic voltammetry through visual aids.
Main Methods:
- Utilized methyl viologen (MV2+) as a redox indicator for visible color changes.
- Employed a homemade thin-layer cell and optical microscopy with digital recording.
- Performed chronoamperometry and cyclic voltammetry experiments.
Main Results:
- Successfully visualized diffusion layer growth and decay.
- Enabled calculation of the diffusion coefficient for methyl viologen radical cation (MV+•).
- Demonstrated the appearance and disappearance of the colored diffusion layer during potential scans.
Conclusions:
- The visual demonstration effectively links observable color changes to electrochemical signals.
- This activity enhances comprehension of fundamental electrochemical processes for students.
- The method is suitable for both introductory and advanced electrochemistry courses.
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