Gas Phase Glycerol Valorization over Ceria Nanostructures with Well-Defined Morphologies.

Autor:	Smith LR; Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K., Sainna MA; Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K., Douthwaite M; Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K., Davies TE; Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K., Dummer NF; Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K., Willock DJ; Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K., Knight DW; Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K., Catlow CRA; Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K., Taylor SH; Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K., Hutchings GJ; Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K.
Jazyk:	angličtina
Zdroj:	ACS catalysis [ACS Catal] 2021 Apr 16; Vol. 11 (8), pp. 4893-4907. Date of Electronic Publication: 2021 Apr 06.
DOI:	10.1021/acscatal.0c05606
Abstrakt:	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. Competing Interests: The authors declare no competing financial interest. (© 2021 The Authors. Published by American Chemical Society.)
Databáze:	MEDLINE
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