Understanding the catalytic activity of gold nanoparticles through multi-scale simulations

Simon Hedegaard Brodersen, Ulrik Grønbjerg Vej-Hansen, Britt Hvolbæk Larsen, Jakob Schiøtz

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

We investigate how the chemical reactivity of gold nanoparticles depends on the cluster size and shape using a combination of simulation techniques at different length scales, enabling us to model at the atomic level the shapes of clusters in the size range relevant for catalysis. The detailed atomic configuration of a nanoparticle with a given number of atoms is calculated by first finding overall cluster shapes with low energy and approximately the right size, and then using Metropolis Monte Carlo simulations to identify the detailed atomic configuration. The equilibrium number of low-coordinated active sites is found, and their reactivities are extracted from models based on Density Functional Theory calculations. This enables us to determine the chemical activity of clusters in the same range of particle sizes that is accessible experimentally. The variation of reactivity with particle size is in excellent agreement with experiments, and we conclude that the experimentally observed trends are mostly explained by the high reactivity of under-coordinated corner atoms on the gold clusters. Other effects, such as the effect of the substrate, may influence the reactivities significantly, but the presence of under-coordinated atoms is sufficient to explain the overall trend.
Original languageEnglish
JournalJournal of Catalysis
Volume284
Issue number1
Pages (from-to)34-41
ISSN0021-9517
DOIs
Publication statusPublished - 2011

Keywords

  • DFT
  • Gold catalysis
  • Multi-scale modelling
  • Monte Carlo

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