Gas phase clycerol valorization over ceria nanostructures with well-defined morphologies

Smith, Louise R., Sainna, Mala A., Douthwaite, Mark, Davies, Thomas E., Dummer, Nicholas F. ORCID: https://orcid.org/0000-0002-0946-6304, Willock, David J. ORCID: https://orcid.org/0000-0002-8893-1090, Knight, David W., Catlow, C. Richard A. ORCID: https://orcid.org/0000-0002-1341-1541, Taylor, Stuart H. ORCID: https://orcid.org/0000-0002-1933-4874 and Hutchings, Graham J. ORCID: https://orcid.org/0000-0001-8885-1560 2021. Gas phase clycerol valorization over ceria nanostructures with well-defined morphologies. ACS Catalysis 11 , pp. 4893-4907. 10.1021/acscatal.0c05606

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Abstract

Glycerol solutions were vaporized and reacted over ceria catalysts with different morphologies to investigate the relationship of product distribution to the surface facets exposed, particularly, the yield of bio-renewable methanol. Ceria was prepared with cubic, rodlike, and polyhedral morphologies via hydrothermal synthesis by altering the concentration of the precipitating agent or synthesis temperature. Glycerol conversion was found to be low over the ceria with a cubic morphology, and this was ascribed to both a low surface area and relatively high acidity. Density functional theory calculations also showed that the (100) surface is likely to be hydroxylated under reaction conditions which could limit the availability of basic sites. Methanol space-time-yields over the polyhedral ceria samples were more than four times that for the cubic material at 400 °C, where 201 g of methanol was produced per hour per kilogram of the catalyst. Under comparable glycerol conversions, we show that the rodlike and polyhedral catalysts produce a major intermediate to methanol, hydroxyacetone (HA), with a selectivity of ca. 45%, but that over the cubic sample, this was found to be 15%. This equates to a 13-fold increase in the space-time-yield of HA over the polyhedral samples compared to the cubes at 320 °C. The implications of this difference are discussed with respect to the reaction mechanism, suggesting that a different mechanism dominates over the cubic catalysts to that for rodlike and polyhedral catalysts. The strong association between exposed surface facets of ceria to high methanol yields is an important consideration for future catalyst design in this area.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Chemistry Cardiff Catalysis Institute (CCI) Advanced Research Computing @ Cardiff (ARCCA)
Publisher:	American Chemical Society
ISSN:	2155-5435
Funders:	EPSRC
Date of First Compliant Deposit:	8 April 2021
Date of Acceptance:	26 March 2021
Last Modified:	14 Nov 2024 08:47
URI:	https://orca.cardiff.ac.uk/id/eprint/140370

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