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Ostwald ripening microkinetic simulation of Au clusters on MgO(0 0 1)

Francis, Samantha, Boucher, Alexandre, Jones, Glenn and Roldan, Alberto 2022. Ostwald ripening microkinetic simulation of Au clusters on MgO(0 0 1). Applied Surface Science 572 , 151317. 10.1016/j.apsusc.2021.151317

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Abstract

Sintering is one of the most common processes responsible for the loss of supported metal nanoparticle catalysts' activity. We have combined ab-initio calculations with microkinetic simulations to investigate the digestion and growth mechanism on Au clusters supported on MgO(0 0 1) following a bottom-up approach. The energy barrier for diffusing a single gold atom on the clean MgO surface was found to be 0.29 eV in full agreement with previous reports. Additionally, and as an extension to the entire energy profile related to Ostwald mechanisms, we found all of the activation energies to be below 1.05 eV in the cases investigated. An odd–even cluster trend was observed during ripening, attributed to the stability of pairing the unpaired electrons associated with the single gold atoms. Microkinetic analyses showed that Au single atoms are present on the surface of magnesia up to a temperature of 160 K. At higher temperatures, the system has enough energy for the single atom to diffuse across the surface and attach to other atoms or clusters. At temperatures akin to room temperature, the cluster undergoes ripening to form larger particles in order to achieve a more stable equilibrium.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Chemistry
Cardiff Catalysis Institute (CCI)
Publisher: Elsevier
ISSN: 0169-4332
Funders: EPSRC
Date of First Compliant Deposit: 18 October 2021
Date of Acceptance: 14 September 2021
Last Modified: 04 Nov 2021 16:10
URI: http://orca.cardiff.ac.uk/id/eprint/144905

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