Development of a ReaxFF potential for Au-Pd

Area of Science:

• Computational Materials Science
• Catalysis
• Nanotechnology

Background:

• Bimetallic alloys like gold-palladium (Au-Pd) offer synergistic effects, outperforming single components in applications such as heterogeneous nanocatalysis.
• Accurate theoretical simulations are essential for designing novel Au-Pd nanocatalyst systems, but ab initio methods like density functional theory (DFT) are computationally limited.
• Atomistic potentials, such as ReaxFF, offer a balance of chemical accuracy and computational efficiency for simulating larger systems and longer timescales.

Purpose of the Study:

• To construct and validate a ReaxFF reactive force-field potential specifically for the gold-palladium (Au-Pd) system.
• To enable reliable atomistic simulations for the rational design of Au-Pd based heterogeneous nanocatalysts.
• To provide accurate parametrizations that can describe experimental bulk properties and phase transitions.

Main Methods:

• Developed ReaxFF potential for Au-Pd using ab initio DFT calculations on various structures (bulk, slabs, nanoparticles) with different stoichiometries.
• Validated the ReaxFF potential through molecular dynamics (MD) and Monte Carlo (MC) simulations.
• Compared simulation results with experimental data for bulk mechanical and thermal properties, and phase transition temperatures.

Main Results:

• Presented several optimal ReaxFF parametrizations for the Au-Pd system.
• The developed potentials accurately describe experimental bulk mechanical and thermal properties of Au-Pd alloys.
• The parametrizations successfully predict atomic order-disorder phase transition temperatures and resulting ordered crystal structures.

Conclusions:

• The validated ReaxFF potential provides a computationally efficient and accurate tool for simulating Au-Pd systems.
• This enables further exploration and rational design of Au-Pd based nanocatalysts for various applications.
• The study establishes robust validation criteria for developing new atomistic potentials.