Strong metal–support interaction in novel core–shell Au–CeO2 nanostructures induced by different pretreatment atmospheres and its influence on CO oxidation. Issue 11 (18th November 2015)

• Record Type: Journal Article
• Authors: Wang, Zhihua; Fu, Huifen; Tian, Ziwei; Han, Dongmei; Gu, Fubo
• Is Part Of: Nanoscale. Volume 8:Issue 11(2016)
• Page Start: 5865
• Page End: 5872
• Publication Date: 2015-11-18
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c5nr06929g
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : Novel core–shell Au–CeO2 nanostructures were synthesized. The strong metal-support interaction between Au and CeO2 can affect the activity of CO oxidation significantly. 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 .