Direct observation of three-dimensional atomic structure of twinned metallic nanoparticles and their catalytic properties

TL;DR

This study used deep learning-assisted atomic electron tomography to determine the full 3D atomic structure of a twinned platinum nanoparticle, revealing how atomic arrangements influence catalytic activity, especially in oxygen reduction reactions.

Contribution

It presents the first detailed 3D atomic structure of a coalesced twinned nanoparticle and links atomic strain and structure to catalytic performance.

Findings

Identification of double twin boundary at the interface

Mapping of full 3D strain tensor in the nanoparticle

Correlation between tensile strain and enhanced catalytic activity

Abstract

We determined a full 3D atomic structure of a dumbbell-shaped Pt nanoparticle formed by a coalescence of two nanoclusters using deep learning assisted atomic electron tomography. Formation of double twin boundary was clearly observed at the interface, while substantial anisotropy and disorder were also found throughout the nanodumbbell. This suggests that the diffusion of interfacial atoms mainly governed the coalescence process, but other dynamic processes such as surface restructuring and plastic deformation were also involved. A full 3D strain tensor was clearly mapped, which allows direct calculation of the oxygen reduction reaction activity at the surface. Strong tensile strain was found at the protruded region of the nanodumbbell, which results in an improved catalytic activity on {100} facets. This work provides important clues regarding the coalescence mechanism and the relation between the atomic structure and catalytic property at the single-atom level.