Quantitative 3D Characterization of Elemental Diffusion Dynamics in Individual Ag@Au Nanoparticles with Different...

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Anisotropic bimetallic nanoparticles are crucial for plasmonic and catalytic applications.
• Their performance depends on metal distribution, which can change with heat exposure.
• Understanding thermal stability is key for practical material applications.

Purpose of the Study:

• To investigate 3D elemental diffusion dynamics in individual anisotropic gold-silver nanoparticles during heating.
• To correlate microstructural properties with thermal stability in heterogeneous nanoparticles.
• To compare alloying dynamics across different nanoparticle shapes and compositions.

Main Methods:

• Utilized quantitative electron tomography in high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) mode.
• Performed *in situ* heating experiments to observe elemental redistribution in real-time.
• Analyzed individual nanoparticles to achieve single-particle level insights.

Main Results:

• Demonstrated a method to study elemental redistribution in complex, asymmetric nanoparticles at the single-particle level.
• Found that nanoparticle shape has no significant effect on alloying speed.
• Observed that nanoparticle composition significantly influences the alloying dynamics.

Conclusions:

• The study provides a novel approach to analyze thermal stability of individual nanoparticles.
• Composition is a critical factor determining alloying speed in gold-silver nanoparticles.
• Estimated diffusion coefficients for metals within individual nanoparticles by comparing experimental data with simulations.