Dynamic Metal-Support Interaction Dictates Cu Nanoparticle Sintering on Al₂O₃ Surfaces.

Area of Science:

• Heterogeneous Catalysis
• Materials Science
• Computational Chemistry

Background:

• Nanoparticle sintering is a major limitation in heterogeneous catalysis, affecting catalyst performance and longevity.
• Understanding the fundamental mechanisms of nanoparticle diffusion and aggregation on support materials is crucial for catalyst design.

Purpose of the Study:

• To investigate the influence of different alumina (Al₂O₃) surfaces on the diffusion and sintering behavior of copper (Cu) nanoparticles.
• To develop and utilize a unified deep potential (DP) model for accurate simulation of nanoparticle-surface interactions.

Main Methods:

• Development of a unified deep potential (DP) model based on the Perdew-Burke-Ernzerhof approximation of density functional theory.
• DP-accelerated molecular dynamics (MD) simulations of Cu nanoparticles on γ-Al₂O₃(100), γ-Al₂O₃(110), and α-Al₂O₃(0001) surfaces.
• Analysis of nanoparticle size-mobility relationships, diffusion mechanisms, and coalescence dynamics.

Main Results:

• Nanoparticle diffusion is strongly dependent on the supporting Al₂O₃ surface; diffusion on γ-Al₂O₃ is size-independent, while on α-Al₂O₃(0001) it decreases with increasing size.
• Faster diffusion of small nanoparticles (<55 atoms) on α-Al₂O₃(0001) is attributed to dynamic metal-support interactions (MSI) involving mobile Al atoms.
• Coalescence of Cu nanoparticles occurs rapidly on α-Al₂O₃(0001) but is inhibited on γ-Al₂O₃ surfaces, highlighting the role of support dynamics in sintering.

Conclusions:

• The dynamics of the supporting surface play a critical role in determining nanoparticle diffusion and sintering mechanisms in heterogeneous catalysis.
• Tailoring the support morphology and its interaction with nanoparticles can effectively control sintering and enhance catalyst stability.
• This study provides fundamental insights for designing advanced, sinter-resistant catalysts through rational engineering of metal-support interfaces.