Abstract
Thin Layer Sonoelectrochemistry (TLS) and the Oxygen Reduction Reaction (ORR) on Platinum
Meeting abstracts (Electrochemical Society), Vol.MA2025-01(57), pp.2760-2760
07/11/2025
DOI: 10.1149/MA2025-01572760mtgabs
Abstract
The kinetics of the oxygen reduction reaction (ORR) are inherently slow, even at platinum electrodes. In low temperature, H2|O2 fuel cells, efficiency is diminished relative to the thermodynamics by ∼25 % because of poor interfacial O2 kinetics. Rather than address slow ORR kinetics by manipulating the chemical composition of the electrocatalyst, physical manipulation of the energy at the electrode | electrolyte interface is effective.
In thin layer sonoelectrochemistry (TLS), constructive interference of sound pressure waves deposits energy selectively at the electrode | electrolyte interface. The ultrasonic oscillator and electrode are separated by a thin layer of electrolyte, about 1 cm thick for a 20 to 40 kHz oscillator. In a well configured TLS cell, interfacial energy is deposited at ∼1 kJ (mol s)-1. Because of constructive interference in TLS, no cavitation and no heating of the electrolyte is observed. Experiments are undertaken with a simple 41 kHz quartz crystal oscillator (QCO). QCOs are voltage driven with minimal energy input. As the system is sonicated, energy deposited at the electrode interface impacts kinetics of slow reactions. Typically, impacts of sonication persist for greater than 10 minutes after sonication ceases.
TLS impacts a variety of reactions that include ORR at platinum and removal of oxide layers on metals such as platinum. Cyclic voltammograms were recorded in a TLS cell that contained 0.1 M aqueous nitric acid.
The standard heterogeneous electron transfer rate k0 for O2 reduction increases ∼50 fold under TLS conditions.
After 20 cyclic voltammetric sweeps over 270 seconds, the Pt oxide peak current is 66 𝜇A without sonication; with sonication, peak current is 19 𝜇A. At 270 s, sonication delivered ~ 270 kJ mol-1 to the electrode | electrolyte interface.
TLS impacts slow interfacial rates by depositing sound pressure energy immediately at the electrode | electrolyte interface. This is a physical rather than a chemical means of electrocatalysis.
Details
- Title: Subtitle
- Thin Layer Sonoelectrochemistry (TLS) and the Oxygen Reduction Reaction (ORR) on Platinum
- Creators
- Chester G. Duda - University of IowaBill Leddy - RE-WD, LLCJohna Leddy - University of Iowa
- Resource Type
- Abstract
- Publication Details
- Meeting abstracts (Electrochemical Society), Vol.MA2025-01(57), pp.2760-2760
- DOI
- 10.1149/MA2025-01572760mtgabs
- ISSN
- 2151-2043
- eISSN
- 2151-2035
- Publisher
- The Electrochemical Society, Inc
- Number of pages
- 1
- Language
- English
- Date published
- 07/11/2025
- Academic Unit
- Chemistry
- Record Identifier
- 9984865444202771
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