Interfacial Reactivity-Triggered Oscillatory Lattice Strains of Nanoalloys

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Designing durable catalysts is crucial for efficient fuel cell performance.
• Understanding nanoalloy structural dynamics under reaction conditions is key to catalyst design.

Purpose of the Study:

• To investigate the dynamic lattice strains of nanoalloys during operation in a proton-exchange membrane fuel cell.
• To elucidate the mechanisms behind nanoalloy structural evolution and its impact on durability.

Main Methods:

• Operando synchrotron high-energy X-ray diffraction.
• Pair distribution function analysis.
• Time-frequency domain transformation and theoretical calculations.

Main Results:

• Observed interfacial reaction-triggered oscillatory lattice strain in alloy nanoparticles during surface dealloying.
• Identified metal atom vacancy diffusion as the origin of oscillatory strain, facilitating realloying.
• Demonstrated that this dynamic process, combined with partial oxidation, enhances nanoalloy durability.

Conclusions:

• The study provides a new guiding principle for engineering durable and self-healable electrocatalysts.
• Understanding dynamic lattice strain is essential for advancing sustainable fuel cell technology.
• Operando measurements offer critical insights into catalyst behavior under working conditions.