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Electrochemo-mechanical coupling in electrocatalytic oxidation of methanol on platinum
Citation Link: https://doi.org/10.15480/882.15814
Publikationstyp
Doctoral Thesis
Date Issued
2025
Sprache
English
Author(s)
Wu, Xinyan
Advisor
Referee
Title Granting Institution
Technische Universität Hamburg
Place of Title Granting Institution
Hamburg
Examination Date
2025-06-23
Institute
TORE-DOI
Citation
Technische Universität Hamburg (2025)
This study investigates the impact of elastic strain on platinum electrode surfaces and its effects on both the adsorption of reactants and the electrocatalytic oxidation of methanol in alkaline solutions. By exploring the coupling between external mechanical modulation and electrocatalytic activity, the research aims to uncover how strain influences both the reaction currents (Faraday currents) and the adsorption enthalpy of methanol and its intermediates.
To explore this coupling effect, two experimental approaches are employed. First, the impact of surface strain on adsorption enthalpy is assessed through surface stress variations, measured via cantilever bending experiments. Second, the strain effect on the overall reaction current is examined using Dynamic Electro-Chemo-Mechanical Analysis (DECMA). Here, a lock-in technique is utilized to capture strain-modulated reaction currents, quantifying them as functions of the applied potential. The study also discusses the role of uncompensated resistance in parameter adjustments, which is crucial for accurately interpreting the intrinsic coupling between externally applied strain and reaction currents on platinum thin film electrode surfaces.
Methanol oxidation reaction (MOR) is selected as the model system due to its importance in various industrial applications, including fuel cells and chemical production. To gain a deeper understanding of the complex electrocatalytic processes involved in MOR, classical electrochemical characterization techniques are employed, such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). These techniques are applied under different parameters and methanol concentrations to capture a comprehensive view of the reaction mechanisms.
The findings reveal that external strain significantly influences the methanol oxidation current. Tensile strain enhances reactivity at low overpotentials, while compressive strain becomes more effective at higher overpotentials, a condition more typical in practical applications. However, the adsorption enthalpy of methanol exhibits negligible dependence on strain, suggesting that the observed changes in electrocatalytic activity are not primarily driven by alterations in methanol adsorption strength. These insights underscore the importance of considering strain effects in the design of high-performance electrocatalysts. Understanding and quantifying how mechanical strain impacts overall reaction rates provides valuable guidance for developing more efficient catalytic materials.
To explore this coupling effect, two experimental approaches are employed. First, the impact of surface strain on adsorption enthalpy is assessed through surface stress variations, measured via cantilever bending experiments. Second, the strain effect on the overall reaction current is examined using Dynamic Electro-Chemo-Mechanical Analysis (DECMA). Here, a lock-in technique is utilized to capture strain-modulated reaction currents, quantifying them as functions of the applied potential. The study also discusses the role of uncompensated resistance in parameter adjustments, which is crucial for accurately interpreting the intrinsic coupling between externally applied strain and reaction currents on platinum thin film electrode surfaces.
Methanol oxidation reaction (MOR) is selected as the model system due to its importance in various industrial applications, including fuel cells and chemical production. To gain a deeper understanding of the complex electrocatalytic processes involved in MOR, classical electrochemical characterization techniques are employed, such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). These techniques are applied under different parameters and methanol concentrations to capture a comprehensive view of the reaction mechanisms.
The findings reveal that external strain significantly influences the methanol oxidation current. Tensile strain enhances reactivity at low overpotentials, while compressive strain becomes more effective at higher overpotentials, a condition more typical in practical applications. However, the adsorption enthalpy of methanol exhibits negligible dependence on strain, suggesting that the observed changes in electrocatalytic activity are not primarily driven by alterations in methanol adsorption strength. These insights underscore the importance of considering strain effects in the design of high-performance electrocatalysts. Understanding and quantifying how mechanical strain impacts overall reaction rates provides valuable guidance for developing more efficient catalytic materials.
Subjects
methanol oxidation reaction
electrochemo-mechanical coupling
Platinum thin film
DDC Class
540: Chemistry
620: Engineering
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