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Understanding Catalyst 'Volcano' Dependence Through Fermi-Level Controlled Kinetics Using Electronic Theory
Nigora Turaeva1, Gregory Yablonsky2, Rebecca Fushimi3
1Department of Natural Sciences and Mathematics, Webster University, Saint Louis, MO 63119, USA.
Entropy (Basel, Switzerland)
|January 8, 2025
Summary
This study expands Michaelis-Menten and Temkin-Boudart mechanisms to a 5-step model, explaining catalytic volcano plots. Catalyst electronic properties influence adsorption and desorption, guiding optimal catalyst selection.
Area of Science:
- Heterogeneous catalysis
- Chemical kinetics
- Materials science
Background:
- Michaelis-Menten and Temkin-Boudart models are foundational in catalysis.
- Catalyst electronic structure significantly impacts reaction rates.
- Volcano-shaped activity trends are commonly observed but not fully explained.
Purpose of the Study:
- To extend existing reaction mechanisms to incorporate catalyst electronic effects.
- To develop a generalized kinetic model explaining catalytic volcano plots.
- To provide a framework for selecting optimal catalysts based on electronic properties.
Main Methods:
- Developed a 5-step reaction mechanism.
- Incorporated fast electronic equilibrium steps.
- Derived a generalized kinetic equation.
Main Results:
- The new kinetic equation explains the volcano-shaped dependence.
- Equilibrium constants of electronic steps influence adsorption/desorption.
- Relative concentrations of charged/neutral intermediates are key.
Conclusions:
- The generalized model offers an alternative explanation for catalytic activity trends.
- Catalyst Fermi level is a critical parameter for optimization.
- This approach is applicable to a wide range of catalytic reactions.
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