Issue 11, 2016

Strong metal–support interaction in novel core–shell Au–CeO2 nanostructures induced by different pretreatment atmospheres and its influence on CO oxidation

Abstract

Yolk–shell Au/CeO2 (Y-Au/CeO2) and encapsulated Au/CeO2 (E-Au/CeO2) nanocatalysts were prepared by using silica templates. A strong metal–support interaction (SMSI) in the Au/CeO2 nanostructures induced by different pretreatment atmospheres and its influence on CO oxidation were studied. E-Au/CeO2 pretreated in O2 had the best performance, followed by Y-Au/CeO2 pretreated in O2, Y-Au/CeO2 pretreated in H2, and E-Au/CeO2 pretreated in H2. The reasons for the different activities were discussed. There were two kinds of strong metal–support interactions (SMSI) between Au and CeO2 termed as R-SMSI (pretreated in reductive atmosphere) and O-SMSI (pretreated in oxidation atmosphere). Because of the smaller size of the Au and the larger contact area, both the R-SMSI and O-SMSI of E-Au/CeO2 were larger than those of Y-Au/CeO2. The O-SMSI was accompanied by the formation of cationic Au species that were beneficial to the enhancing of activity. As expected, the activity of E-Au/CeO2 pretreated in O2 with a Au size less than 5 nm was higher than that of Y-Au/CeO2 pretreated in O2 with 25 nm Au. However, it is surprisingly found that the activity of Y-Au/CeO2 pretreated in H2 with 25 nm Au was higher than that of E-Au/CeO2 pretreated in H2 with a Au size less than 5 nm. R-SMSI resulted in the formation of a AuCe alloy that had a negative effect on the activity. Compared with E-Au/CeO2 pretreated in H2, Y-Au/CeO2 pretreated in H2 exhibited a smaller relative content of the AuCe alloy, leading to a better activity of Y-Au/CeO2 pretreated in H2.

Graphical abstract: Strong metal–support interaction in novel core–shell Au–CeO2 nanostructures induced by different pretreatment atmospheres and its influence on CO oxidation

Supplementary files

Article information

Article type
Paper
Submitted
07 Oct 2015
Accepted
21 Oct 2015
First published
04 Nov 2015

Nanoscale, 2016,8, 5865-5872

Strong metal–support interaction in novel core–shell Au–CeO2 nanostructures induced by different pretreatment atmospheres and its influence on CO oxidation

Z. Wang, H. Fu, Z. Tian, D. Han and F. Gu, Nanoscale, 2016, 8, 5865 DOI: 10.1039/C5NR06929G

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