Mr. Yue Wang - M.Sc. Candidate
17/11/2024
ZOOM
14:30 (Jerusalem time) | 20:30 (Beijing time)
For nanoalloy of multi-metallic components, equilibrium structures are always of importance since they affect their physical and chemical properties and resultant potential applications. When a nanoalloy particle is anchored onto a specific substrate, a portion of it (all of it, if small enough) may become epitaxially aligned with the substrate, which might occur even if the lattice mismatch between the contacted surface of the nanoparticle and the substrate is significant. This inspired the investigation of a usually neglected tunable parameter, that is the strain that can be induced via stretching or compressing the support. In our current work, we constructed a group of truncated octahedral Ni-Pt alloy nanoparticles of different sizes and compositions and investigated their relaxation under various straining conditions using a combination of molecular dynamics and Monte Carlo simulation methods. Our results demonstrated that the inherent atomic segregation trend is firm even under exaggerated strains. Meanwhile, strain engineering led to atomic sinking and leaching through the bottom atomic layer of our nanoalloys. In addition, we found the radial concentration variance of the minority component, which suggests possible trends for ordered phases. More importantly, we found that strain engineering might trigger the generation of potential new facets and new stacking in some atomic ensembles (from fcc to hcp). These strain-induced structural transformations are expected to be utilized in design for solid catalysts.