Simulation of Deformation Mechanisms in Coated and Uncoated Platinum Nanoparticles

Single-digit-nanometer particles are the building blocks for emerging energy technologies, but the complex interrelationships between their size, shape, and mechanical properties are still not fully understood. Particularly, for the smallest nanoparticles, the traditional “smaller is stronger” trend may not apply, and deformation can occur through both atom diffusion and dislocations. Decreasing particle size leads to a greater percent of surface atoms with lower activation energy for diffusion and therefore more diffusion-mediated deformation. Surface energy can be modified by coating nanoparticles, so coatings are expected to affect the relative contributions of diffusion vs. dislocations to deformation. In this study, we used classical molecular dynamics simulation to study the deformation mechanisms of platinum nanoparticles of various shapes and sizes, with and without a surface coating of another metal or oxide. Compression tests were performed on both coated and uncoated nanoparticles to investigate the link between surface energy and deformation mechanisms. Our study contributes to the understanding of nanoparticle deformation which is crucial for designing nanoparticle-based energy systems.