Interplay between shape and composition in bimetallic nanoparticles revealed by an efficient optimal-exchange...

Area of Science:

• Materials Science
• Nanotechnology
• Computational Chemistry

Background:

• Bimetallic nanoparticles are crucial for heterogeneous catalysis.
• Understanding the link between nanoparticle shape and composition is vital but challenging.

Purpose of the Study:

• To investigate the relationship between shape and elemental composition in bimetallic nanoparticles.
• To determine the lowest energy configurations for platinum-gold (PtAu) nanoparticles.

Main Methods:

• Implementation and application of global optimization methods.
• Utilizing an efficient optimal-exchange algorithm.
• Leveraging local atomic contributions to an empirical surrogate energy expression.

Main Results:

• The most stable shape of PtAu nanoparticles transitions from symmetric to distorted forms as composition changes.
• Identified optimal atom exchanges by analyzing local atomic contributions.
• Uncovered the origin of stability in distorted shapes due to favorable energy trade-offs.

Conclusions:

• Particle shape significantly influences the stability and properties of bimetallic nanoparticles.
• Distorted shapes in PtAu nanoparticles arise from specific atomic coordination preferences (Pt over-coordination, Au under-coordination).
• The developed method provides insights into designing nanoparticles for catalysis.