Tailoring Local Chemical Ordering via Elemental Tuning in High-Entropy Alloys

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• High-entropy alloys (HEAs) offer vast compositional possibilities for advanced applications.
• Understanding local atomic and elemental configurations in HEAs, especially noble-metal-based nanomaterials, is crucial but challenging.
• Current knowledge gaps hinder the rational design of nano-HEAs for energy conversion and catalysis.

Purpose of the Study:

• To precisely determine atomic-level structural and elemental arrangements in model HEAs (RhPtPdFeCo and RuPtPdFeCo).
• To investigate the impact of single-element substitution on elemental distribution and ordering.
• To demonstrate control over local ordering in HEAs by adjusting elemental concentrations.

Main Methods:

• Synthesis of model high-entropy alloy nanomaterials.
• Advanced characterization techniques to probe atomic-level structure and elemental distribution.
• Systematic variation of constituent elements and their concentrations.

Main Results:

• Substitution of Rh with Ru in HEAs induced significant changes from random mixing to local elemental ordering.
• Local ordering in Ru-containing HEAs could be tuned by varying Ru concentration.
• Demonstrated ability to control local Ru clustering and form distinct heterostructures.

Conclusions:

• Developed a practical method for manipulating local atomic structures and elemental arrangements in noble-metal-based HEAs.
• Provided fundamental insights into the structure-property relationships of HEA nanomaterials.
• Laid groundwork for mechanistic understanding and design of HEAs in catalysis and energy conversion.