Masoud Shahrokhi publikoval nový článek!

Stability of single-atom Pt-alloyed cu clusters supported on γ-Al₂O₃: A DFT study of size and oxidizing environment effects

Odkaz zde: https://doi.org/10.1016/j.commatsci.2025.114346

Abstrakt:

Single-Cluster Catalysts (SCCs) have garnered significant interest due to their high atom economy, stability, activity, and selectivity in various chemical reactions. In this work, density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations are employed to study the stability, structural evolution, electronic properties, and charge transfer characteristics of Cu₁₂Pt₁ clusters supported on γ-alumina in an oxidizing environment. In the absence of oxygen, the supported cluster adopts a compact trilayered geometry. In contrast, it transforms into a bilayered structure under low oxygen coverage and develops into a dome-like shape at the highest coverage. This structural transformation demonstrates intrinsic metastability and high ductility of the cluster, which enables it to adsorb a wide range of oxygen contents through reconstruction, in contrast to the more rigid extended surfaces. Our results reveal the significant influence of oxygen-adsorbed coverages on the Cu₁₂Pt₁ cluster‘s morphological evolution, electronic properties, and thermodynamic phase diagram compared to the extended Cu(111) and Cu₁₅Pt₁(111) surfaces. These results indicate that size effects play a more dominant role than alloying effects for the oxidation of sub-nanometer CuPt nanoparticles.