On the Structural Origin of the Catalytic Properties of Inherently Strained Ultrasmall Decahedral Gold Nanoparticles

TL;DR

This paper explains the high catalytic activity of small, strained decahedral gold nanoparticles through atomic structural analysis and theoretical calculations, revealing how inherent strain enhances reactivity.

Contribution

It introduces a new mechanism linking structural strain in gold nanoparticles to their catalytic properties, supported by experimental and computational evidence.

Findings

Surface nearest neighbor distances expanded by 5.6% on average

Atomic strains exceed 10% in many regions

Density functional theory predicts enhanced CO oxidation activity

Abstract

A new mechanism for reactivity of multiply twinned gold nanoparticles resulting from their inherently strained structure provides a further explanation of the surprising catalytic activity of small gold nanoparticles. Atomic defect structural studies of surface strains and quantitative analysis of atomic column displacements in the decahedral structure observed by aberration corrected transmission electron microscopy reveal an average expansion of surface nearest neighbor distances of 5.6 percent, with many strained by more than 10 percent. Density functional theory calculations of the resulting modified gold d-band states predict significantly enhanced activity for carbon monoxide oxidation. The new insights have important implications for the applications of nanoparticles in chemical process technology, including for heterogeneous catalysis.