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A Simple, Low-cost, and Robust System to Measure the Volume of Hydrogen Evolved by Chemical Reactions with Aqueous Solutions
Published on: August 17, 2016
A model for the Heyrovsky reaction as the second step in hydrogen evolution
E Santos1, P Hindelang, P Quaino
1Faculdad de Matemática, Astronomía y Física, IFEG-CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina.
Physical Chemistry Chemical Physics : PCCP
|March 16, 2011
Summary
Researchers modeled the Heyrovsky reaction in hydrogen evolution, finding that electron transfer to a proton is the rate-limiting step. This occurs as the proton approaches the electrode, with the hydrogen intermediate moving away to reduce repulsion.
Area of Science:
- Electrochemistry
- Surface Science
- Computational Chemistry
Background:
- The Heyrovsky reaction is a key step in hydrogen evolution on electrode surfaces.
- Understanding the kinetics and mechanism of this reaction is crucial for catalysis and energy applications.
Purpose of the Study:
- To develop a model Hamiltonian for the Heyrovsky reaction.
- To investigate the rate-determining step and molecular dynamics at the electrode-solution interface.
- To present explicit results for a silver (Ag(111)) electrode.
Main Methods:
- Development of a model Hamiltonian.
- Extensive density-functional theory (DFT) calculations.
- Analysis of reaction pathways and transition states.
Main Results:
- The rate-determining step was identified as electron transfer to the proton.
- The adsorbed hydrogen intermediate moves away from the surface at the saddle point to minimize repulsion.
- Electron transfer occurs near the H-H bond distance in molecular hydrogen.
Conclusions:
- The developed model provides insights into the Heyrovsky reaction mechanism.
- Surface dynamics, specifically the movement of intermediates, play a significant role in reaction rates.
- DFT calculations are essential for detailed mechanistic studies in electrocatalysis.
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