Toward atomically-precise synthesis of supported bimetallic nanoparticles using atomic layer deposition.

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• Multi-metallic nanoparticles offer tunable properties through composition, atomic ordering, and size.
• Supported bimetallic nanoparticles are crucial for catalysis and electrocatalysis.
• Traditional synthesis methods lack precise control, resulting in mixed compositions.

Purpose of the Study:

• To develop a general strategy for synthesizing supported bimetallic nanoparticles with precise control.
• To avoid the formation of monometallic nanoparticles during synthesis.
• To precisely control the size, composition, and structure of bimetallic nanoparticles.

Main Methods:

• Utilizing atomic layer deposition (ALD) for selective secondary metal growth on primary metal nanoparticles.
• Tailoring precursor pulse sequences to control nanoparticle characteristics.
• Employing in situ Fourier transform infrared spectroscopy (FTIR) of CO chemisorption for surface composition analysis.
• Using aberration-corrected scanning transmission electron microscopy (STEM) for structural confirmation.

Main Results:

• Achieved selective growth of the secondary metal exclusively on primary metal nanoparticles, preventing monometallic formation.
• Demonstrated precise control over bimetallic nanoparticle size, composition, and atomic structure.
• In situ FTIR provided real-time insights into atomic-scale surface evolution.
• Aberration-corrected STEM confirmed the controlled synthesis and structure.

Conclusions:

• Atomic layer deposition offers a general and precise method for synthesizing supported bimetallic nanoparticles.
• This controlled synthesis approach overcomes limitations of traditional methods.
• The developed technique enables the precise tuning of bimetallic nanoparticle properties for advanced catalytic applications.