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Hydrogen Production and Utilization in a Membrane Reactor
Published on: March 10, 2023
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Elucidating the Electrochemical Hydrogenation Route by Spatially Isolating Competing Pathways
Jiguang Zhang1,2, Chengyi Zhang3, Sibo Wang1
1Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, 117585, Republic of Singapore.
Journal of the American Chemical Society
|July 11, 2025
Summary
Electrochemical hydrogenation occurs via two pathways: Eley-Rideal and Langmuir-Hinshelwood. This study differentiates their kinetics, showing Langmuir-Hinshelwood has a larger kinetic isotope effect, influencing product selectivity.
Area of Science:
- Electrochemistry
- Chemical reaction mechanisms
Background:
- Electrochemical hydrogenation proceeds via Eley-Rideal or Langmuir-Hinshelwood mechanisms.
- Understanding pathway competition is crucial for reaction selectivity and rates.
Purpose of the Study:
- To differentiate the kinetic isotope effects of Eley-Rideal and Langmuir-Hinshelwood pathways in electrochemical hydrogenation.
- To investigate factors influencing pathway preference, such as steric hindrance.
Main Methods:
- Utilized a palladium membrane reactor to isolate the Langmuir-Hinshelwood pathway.
- Employed kinetic isotope effect (KIE) measurements using H2O/D2O electrolytes.
- Performed theoretical simulations to support experimental findings.
Main Results:
- The Langmuir-Hinshelwood pathway exhibits a larger kinetic isotope effect than the Eley-Rideal pathway.
- Eley-Rideal pathway shows higher deuterium incorporation with mixed H2O/D2O electrolytes.
- Increased steric hindrance favors the Langmuir-Hinshelwood pathway.
Conclusions:
- Distinct kinetic behaviors of hydrogenation pathways were elucidated.
- Findings provide insights for computational modeling and catalyst design in electrochemical hydrogenation.
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