New insights into the activation and deactivation of Au/CeZrO4 in the low-temperature water-gas shift reaction

Hutchings, Graham John ORCID: https://orcid.org/0000-0001-8885-1560, Carter, James, Liu, Xi, He, Qian ORCID: https://orcid.org/0000-0003-4891-3581, Althahban, Sultan, Nowicka, Ewa ORCID: https://orcid.org/0000-0001-7449-2720, Freakley, Simon, Niu, Liwei, Morgan, David ORCID: https://orcid.org/0000-0002-6571-5731, Li, Yongwang, Niemantsverdriet, Hans ORCID: https://orcid.org/0000-0002-0743-0850, Golunski, Stanislaw ORCID: https://orcid.org/0000-0001-7980-8624 and Kiely, Christopher ORCID: https://orcid.org/0000-0001-5412-0970 2017. New insights into the activation and deactivation of Au/CeZrO4 in the low-temperature water-gas shift reaction. Angewandte Chemie International Edition 56 (50) , pp. 16037-16041. 10.1002/anie.201709708

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Abstract

Gold (Au) on ceria–zirconia is one of the most active catalysts for the low-temperature water–gas shift reaction (LTS), a key stage of upgrading H2 reformate streams for fuel cells. However, this catalyst rapidly deactivates on-stream and the deactivation mechanism remains unclear. Using stop–start scanning transmission electron microscopy to follow the exact same area of the sample at different stages of the LTS reaction, as well as complementary X-ray photoelectron spectroscopy, we observed the activation and deactivation of the catalyst at various stages. During the heating of the catalyst to reaction temperature, we observed the formation of small Au nanoparticles (NPs; 1–2 nm) from subnanometer Au species. These NPs were then seen to agglomerate further over 48 h on-stream, and most rapidly in the first 5 h when the highest rate of deactivation was observed. These findings suggest that the primary deactivation process consists of the loss of active sites through the agglomeration and possible dewetting of Au NPs.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Chemistry Cardiff Catalysis Institute (CCI)
Subjects:	Q Science > QD Chemistry
Publisher:	Wiley-VCH Verlag
ISSN:	1433-7851
Date of First Compliant Deposit:	19 October 2017
Date of Acceptance:	10 October 2017
Last Modified:	07 Nov 2024 22:45
URI:	https://orca.cardiff.ac.uk/id/eprint/105685

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