Microkinetic Model to Rationalize the Lifetime of Electrocatalysis: Trade-off between Activity and Stability.

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Long-term operational stability is critical for electrocatalysts used in sustainable hydrogen and chemical production.
• Current challenges in designing durable electrocatalysts stem from a lack of quantitative predictive frameworks for catalytic lifetimes.
• Electrocatalyst deactivation, often through dissolution, limits practical application and necessitates improved material design strategies.

Purpose of the Study:

• To develop a quantitative conceptual framework for predicting the operational lifetime of electrocatalysts.
• To establish a microkinetic equation that accurately models electrocatalyst deactivation via dissolution.
• To elucidate the relationship between catalytic activity and material stability.

Main Methods:

• Developed a microkinetic equation by applying the quasi steady-state approximation to model irreversible, first-order elementary reactions.
• Modeled electrocatalyst deactivation as a process of dissolution.
• Analyzed the correlation between catalytic rates and deactivation rates under simplified reaction conditions.

Main Results:

• Derived a microkinetic equation that quantifies electrocatalyst lifetime during dissolution.
• Established a linear correlation between catalytic rate and deactivation rate, revealing an activity-stability trade-off.
• Validated the model using a manganese oxide electrocatalyst for the oxygen evolution reaction, showing strong agreement between theoretical and experimental lifetimes (r^2 = 0.86).

Conclusions:

• The developed microkinetic equation provides a quantitative tool to predict electrocatalyst lifetimes.
• The findings highlight an inherent trade-off between electrocatalytic activity and stability, essential for rational material design.
• This framework is crucial for advancing the development of durable electrocatalysts for sustainable energy applications.