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CO oxidation and COPrOx over preformed Au nanoparticles supported over nanoshaped CeO2

Paper ID Volume ID Publish Year Pages File Format Full-Text
45496 46413 2016 9 PDF Available
Title
CO oxidation and COPrOx over preformed Au nanoparticles supported over nanoshaped CeO2
Abstract

•CO oxidation and COPrOx are tested over Au supported on nanoshaped ceria.•The effect of exposed planes is determined by using preformed Au nanoparticles.•There is a trend between catalytic activity and electron transfer between Au and Ce.•Over {1 1 0} facets (nanorods) Au oxidizes and Ce(III) species increases.•No electron transfer occurs between Au metal and ceria nanocubes ({1 0 0} facets).

Au/CeO2 (0.25% wt. Au) catalysts were prepared by anchoring preformed Au nanoparticles over ceria polycrystals, cubes and rods and tested in the oxidation of CO and COPrOx. The use of preformed Au nanoparticles assured a constant Au particle size (ca. 5 nm by HRTEM) for all samples, which allowed to a precise assessment of the effect of the morphology of nanoshaped ceria on catalytic activity. The catalytic performance of the Au/CeO2-rods was much better than that of the Au/CeO2-polycrystals and Au/CeO2-cubes both in the oxidation of CO and COPrOx reactions. The Au/CeO2-rods exhibited the highest amount of oxidized Au and Ce(III) species by XPS, whereas in the Au/CeO2-cubes gold was totally metallic and the amount of Ce(III) was minimum. An intermediate situation was encountered in the Au/CeO2-polycrystals. Considering the differences in the oxidation states of Au and Ce and the fact that all samples were prepared with preformed metallic Au nanoparticles of the same size, the results indicate that the intrinsic nature of the different ceria surfaces exerts a prominent role in the gold-ceria interaction and in the electron density transfer from Au to Ce, which in turn has a strong effect on catalytic activity. Gold nanoparticles strongly interact with CeO2-{1 1 0} surfaces with respect to CeO2-{1 1 1} and CeO2-{1 0 0}, even when Au nanoparticles are prepared separately and simply deposited by impregnation.

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Keywords
CO oxidation; Preferential CO oxidation; Ceria; Nanocubes; Nanorods; XPS
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CO oxidation and COPrOx over preformed Au nanoparticles supported over nanoshaped CeO2
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 197, 15 November 2016, Pages 47–55
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us