Dynamic Interfacial Reaction Rates from Electrochemistry-Mass Spectrometry

Area of Science:

• Electrochemistry
• Analytical Chemistry
• Physical Chemistry

Background:

• Electrochemistry-mass spectrometry (EC-MS) offers high temporal resolution for studying interfacial Faradaic reaction rates.
• Mass spectrometric signals in EC-MS are often confounded by mass transport effects, preventing direct correlation with partial current densities.
• Accurate quantification of interfacial reaction dynamics requires addressing these mass transport limitations.

Purpose of the Study:

• To develop a mathematical framework for deconvoluting mass transport effects in EC-MS signals.
• To enable the quantitative determination of true dynamic partial current densities from EC-MS measurements.
• To investigate the fundamental time-resolution limitations of EC-MS.

Main Methods:

• Development of a mass transport model tailored for EC-MS.
• Application of deconvolution techniques to measured mass spectrometer signals.
• Validation using impulse response analysis of hydrogen and oxygen evolution reactions.
• Analysis of dynamic phenomena in acidic electrolytes.

Main Results:

• A novel mathematical framework was established to extract partial current densities from EC-MS data.
• The study identified entropy-driven mass transport processes as a key limitation on EC-MS time resolution.
• The methodology was successfully validated against model predictions for hydrogen and oxygen evolution.
• Dynamic behaviors during hydrogen and oxygen evolution were elucidated.

Conclusions:

• The developed deconvolution framework provides a quantitative link between EC-MS signals and partial current densities.
• Understanding mass transport limitations is crucial for optimizing EC-MS temporal resolution.
• This approach advances the study of dynamic interfacial electrochemical processes.