Revealing 3-dimensional core-shell interface structures at the single-atom level

TL;DR

This study uses atomic electron tomography to reveal the full 3D atomic structure and strain distribution of Pd@Pt core-shell nanoparticles, linking atomic-scale strain to catalytic activity.

Contribution

It provides the first detailed 3D atomic and strain mapping of core-shell nanoparticles at the single-atom level, connecting structure to catalytic function.

Findings

Revealed 3D atomic structure and strain profiles of Pd@Pt nanoparticles.

Identified shape-dependent anisotropic strain distributions.

Predicted surface catalytic activity based on strain analysis.

Abstract

Nanomaterials with core-shell architectures are prominent examples of strain-engineered materials, where material properties can be designed by fine-tuning the misfit strain at the interface. Here, we elucidate the full 3D atomic structure of Pd@Pt core-shell nanoparticles at the single-atom level via atomic electron tomography. Full 3D displacement fields and strain profiles of core-shell nanoparticles were obtained, which revealed a direct correlation between the surface and interface strain. It also showed clear Poisson effects at the scale of the full nanoparticle as well as the local atomic bonds. The strain distributions show a strong shape-dependent anisotropy, whose nature was further corroborated by molecular statics simulations. From the observed surface strains, the surface oxygen reduction reaction activities were predicted. These findings give a deep understanding of structure-property relationships in strain-engineerable core-shell systems, which could pave a new way toward direct control over the resulting catalytic properties.