Three-layer core/shell structure in Au-Pd bimetallic nanoparticles

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Understanding nanoparticle morphology is crucial for controlling their properties.
• Gold-palladium (Au-Pd) nanoparticles are of interest due to their tunable catalytic and electronic properties.

Purpose of the Study:

• To elucidate the internal structure of Au-Pd nanoparticles.
• To characterize the composition and arrangement of elements within the nanoparticle layers.

Main Methods:

• Transmission electron microscopy (TEM) was employed.
• Spatially resolved imaging, spectroscopy, and diffraction modes of TEM were utilized.

Main Results:

• A novel three-layer core/shell morphology was identified in Au-Pd nanoparticles.
• The structure consists of an evenly alloyed inner core, an intermediate gold-rich (Au-rich) layer, and an outer palladium-rich (Pd-rich) shell.
• Intimate alloying between gold and palladium was confirmed across all layers.

Conclusions:

• The discovered core/shell structure provides new insights into Au-Pd nanoparticle formation.
• The detailed understanding of layer composition is essential for designing nanoparticles with specific functionalities.
• Spatially resolved TEM is a powerful technique for characterizing complex nanoparticle architectures.