Multistep Nucleation of High-Entropy Alloy Nanoparticles

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• High-entropy alloy (HEA) nanoparticles (NPs) show promise for catalysis and energy storage.
• Understanding HEA NP formation mechanisms is crucial for property optimization.
• Current knowledge of nanoscale nucleation and growth in HEA NPs is limited.

Purpose of the Study:

• To elucidate the nanoscale mechanisms of FeCoNiRhPt HEA NP formation.
• To investigate the sequential alloying process during synthesis.
• To provide fundamental insights into multimetallic material synthesis.

Main Methods:

• Utilized in situ transmission electron microscopy (TEM).
• Observed the thermal-reduction-based synthesis of HEA NPs directly from precursors.

Main Results:

• Observed burst nucleation of amorphous RhPt (a-RhPt) clusters.
• Demonstrated crystallization of a-RhPt clusters into crystalline RhPt (c-RhPt) alloy NPs.
• Showed subsequent incorporation of Fe, Co, and Ni into c-RhPt NPs to form stable HEA NPs.

Conclusions:

• HEA NP formation follows a sequential alloying pathway.
• Intermediate stages of alloying are critical for stable HEA NP formation.
• Findings offer insights applicable to the broader synthesis of multimetallic nanomaterials.