Sub-nanometer dimensions control of core/shell nanoparticles prepared by atomic layer deposition

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• Bimetallic core/shell nanoparticles (NPs) exhibit unique properties valuable for catalysis.
• Precise control over core and shell dimensions is crucial for optimizing catalytic performance.

Purpose of the Study:

• To demonstrate sub-nanometer control over Pd/Pt core/shell NP dimensions using atomic layer deposition (ALD).
• To establish conditions for accurate dimension control and explore catalyst stability and deposition on complex substrates.

Main Methods:

• Utilized atomic layer deposition (ALD) for sequential deposition of Pd and Pt.
• Investigated the influence of surface energy, linear growth, and selective shell deposition on NP morphology.
• Determined the minimum core diameter required for catalytic precursor dissociation.

Main Results:

• Achieved sub-nanometer control over both Pd/Pt core and shell dimensions.
• Identified key conditions for island growth, monodispersed NP formation, and controlled shell thickness.
• Established a 1 nm minimum core diameter for catalytic precursor dissociation during shell growth.
• Demonstrated ALD's capability for depositing NPs on high aspect ratio substrates like nanowires.

Conclusions:

• ALD offers a novel strategy for precisely controlling bimetallic core/shell NP dimensions.
• The findings pave the way for developing highly tuneable heterogeneous catalysts.
• ALD shows significant potential for advanced catalyst preparation, including on complex nanostructures.