Three-dimensional Atomic Mapping of Ligands on Nanoparticles

TL;DR

This study uses atom probe tomography to visualize and analyze the 3D atomic distribution of ligands on Pd nanoparticles, revealing how halide ions influence ligand adsorption and nanoparticle surface stabilization.

Contribution

First direct 3D atomic-scale imaging of ligand distribution on nanoparticles, linking ligand interactions with surface stabilization mechanisms.

Findings

Br ions promote cetrimonium adsorption via electrostatic interactions.

Ligand distribution influences nanoparticle surface stabilization.

Validated results with density functional theory.

Abstract

Capping ligands are crucial to synthesize colloidal nanoparticles with novel functional properties. However, the interaction between capping ligands and their interaction with the crystallographic surfaces of nanoparticles during colloidal synthesis remains a great mystery, due to the lack of direct imaging techniques. In this study, atom probe tomography was adopted to investigate the three-dimensional atomic-scale distribution of two of the most common types of these ligands, cetrimonium and halide (Br and Cl) ions, on Pd nanoparticles. The results, validated using the density functional theory, demonstrated that the Br anions adsorbed on the nanoparticle surfaces promote the adsorption of the cetrimonium cations through electrostatic interactions, stabilizing the Pd {111} facets.