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Electrochemical Detection of Deuterium Kinetic Isotope Effect on Extracellular Electron Transport in Shewanella oneidensis MR-1
Published on: April 16, 2018
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Kinetic Isotope Effects Quantify pH-Sensitive Water Dynamics at the Pt Electrode Interface.
Luis Rebollar1, Saad Intikhab1, Joshua D Snyder1
1Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States.
The Journal of Physical Chemistry Letters
|March 4, 2020
Summary
Interfacial water dynamics significantly impact hydrogen reaction kinetics, especially in alkaline solutions, according to kinetic isotope effect (KIE) voltammetry. This study highlights the crucial role of solvent dynamics in electrocatalysis.
Area of Science:
- Surface electrochemistry
- Electrocatalysis
- Physical chemistry
Background:
- The pH-dependent kinetics of hydrogen oxidation and evolution reactions (HORs/HERs) are poorly understood.
- The influence of interfacial water networks on reaction rates is a key area of investigation.
Purpose of the Study:
- To quantify the role of interfacial water dynamics in hydrogen reaction kinetics.
- To investigate surface-specific kinetic isotope effects (KIEs) on platinum single crystals.
Main Methods:
- Kinetic isotope effect (KIE) voltammetry experiments.
- Utilized single-crystal platinum electrodes (Pt(111) and Pt(110)).
- Conducted experiments in both acidic and alkaline electrolytes.
Main Results:
- A surface-sensitive KIE was observed for both HER and HOR, measurable in base but not in acid.
- The HOR on Pt(111) in KOD showed a significant KIE (up to 3.4), exceeding expected secondary KIE values.
- No measurable KIE was found for the HOR in DClO4, indicating minimal solvent dynamic influence in acid.
Conclusions:
- Interfacial solvent dynamics are critical for alkaline hydrogen electrocatalysis.
- Acidic conditions show limited influence from solvent dynamics on hydrogen reactions.
- These findings emphasize the importance of 'beyond adsorption' effects in electrocatalysis.
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