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Generation and Control of Electrohydrodynamic Flows in Aqueous Electrolyte Solutions
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Accelerating water dissociation in bipolar membranes and for electrocatalysis
Sebastian Z Oener1, Marc J Foster2, Shannon W Boettcher1
1Department of Chemistry and Biochemistry, the Materials Science Institute, and the Oregon Center for Electrochemistry, University of Oregon, Eugene, OR 97403, USA. szo@uoregon.edu swb@uoregon.edu.
Science (New York, N.Y.)
|July 4, 2020
Summary
Efficient water dissociation (WD) is key for bipolar membranes and electrocatalysis. This study demonstrates a novel BPM electrolyzer achieving low overpotentials for WD, enabling efficient pure water electrolysis.
Area of Science:
- Electrochemistry
- Materials Science
- Chemical Engineering
Background:
- Water dissociation (WD) is crucial for fabricating bipolar membranes (BPMs) and enhancing electrocatalytic reactions in neutral to alkaline conditions.
- Efficient WD catalysis is needed to overcome kinetic limitations in electrochemical devices operating with water.
Purpose of the Study:
- To design and evaluate a BPM electrolyzer for quantitatively measuring WD kinetics.
- To correlate WD activity with alkaline hydrogen evolution reaction (HER) activity for metal nanoparticles.
- To develop an efficient BPM system for pure water electrolysis.
Main Methods:
- Fabrication of a BPM electrolyzer for in-situ WD kinetics measurement.
- Utilizing metal nanoparticles and metal-oxide catalysts with varying pH efficiencies.
- Electrochemical characterization including overpotential and voltage measurements at different current densities.
Main Results:
- WD activity of metal nanoparticles was found to correlate with alkaline HER activity.
- A combined catalyst system achieved WD overpotentials below 10 mV at 20 mA·cm⁻².
- Pure water BPM electrolyzers operated at 500 mA·cm⁻² with a total voltage of approximately 2.2 V.
Conclusions:
- The developed BPM electrolyzer accurately quantifies WD kinetics.
- Optimized catalyst combinations significantly reduce overpotentials for water dissociation.
- This technology enables efficient pure water electrolysis for various electrochemical applications.
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