Three-dimensional atomic-scale structure of size-selected gold nanoclusters

Area of Science:

• Materials Science
• Nanotechnology
• Chemistry

Background:

• Determining the 3D structure of nanoparticles is crucial for understanding their properties, but challenging for ultrasmall, unstable clusters.
• Traditional electron tomography is limited by sample stability and electron beam interactions.

Purpose of the Study:

• To develop a method for atomic-resolution 3D structure determination of preformed, size-selected gold nanoclusters.
• To investigate the structural geometries of gold nanoclusters and their relation to catalytic activity.

Main Methods:

• Utilized aberration-corrected scanning transmission electron microscopy (STEM).
• Employed simple imaging simulations for structural analysis.
• Soft-landed gas-phase synthesized gold nanoclusters onto an amorphous carbon substrate.

Main Results:

• Achieved atomic resolution to determine size, 3D shape, orientation, and atomic arrangement of gold nanoclusters.
• Identified specific geometries (Icosahedral, Cuboctahedral, Ino-decahedral) for gold nanoclusters with 3096 atoms.
• Results align with theoretical modeling and energetic considerations.

Conclusions:

• Aberration-corrected STEM provides a viable method for characterizing ultrasmall, supported metal nanoclusters.
• Detailed structural information is essential for understanding size- and structure-specific catalytic reactions of gold nanoclusters.
• The technique is applicable to other supported ultrasmall metal cluster systems.