The Structure of Sub-nm Platinum Clusters at Elevated Temperatures

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• Metallic clusters, especially those with fewer than a dozen atoms, are crucial for catalysis and crystal nucleation but remain poorly understood.
• Scanning transmission electron microscopy (STEM) offers atomic resolution but is limited by time resolution for dynamic processes.

Purpose of the Study:

• To investigate the structure and stability of platinum (Pt) clusters on carbon, a key catalytic system.
• To overcome the time-resolution limitations of traditional STEM for studying dynamic atomic structures.

Main Methods:

• Utilized fast dynamic STEM combined with a spatio-temporal image denoising algorithm.
• Performed experimental and theoretical analyses of Pt clusters on a carbon support.

Main Results:

• Observed dynamic amorphous 2D structures of Pt clusters at room temperature.
• Found that Pt clusters transform into a crystalline state above approximately 300°C.
• Demonstrated a strong tendency for crystalline clusters to adopt the face-centered cubic (FCC) bulk structure of Pt, with cuboidal geometries being most prevalent.

Conclusions:

• Fast dynamic STEM with denoising is effective for studying atomic structures of small metallic clusters.
• Platinum clusters exhibit distinct structural transitions with temperature, favoring bulk-like FCC structures at higher temperatures.
• The findings provide critical insights into the behavior of nanomaterials relevant to catalysis and crystal nucleation.