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Title: Reactivity of Pd–MO 2 encapsulated catalytic systems for CO oxidation
In this study, we present an investigation aimed at characterizing and understanding the synergistic interactions in encapsulated catalytic structures between the metal core ( i.e. , Pd) and oxide shell ( i.e. , TiO 2 , ZrO 2 , and CeO 2 ). Encapsulated catalysts were synthesized using a two-step procedure involving the initial colloidal synthesis of Pd nanoparticles (NPs) capped by various ligands and subsequent sol–gel encapsulation of the NPs with porous MO 2 (M = Ti, Zr, Ce) shells. The encapsulated catalytic systems displayed higher activity than the Pd/MO 2 supported structures due to unique physicochemical properties at the Pd–MO 2 interface. Pd@ZrO 2 exhibited the highest catalytic activity for CO oxidation. Results also suggested that the active sites in Pd encapsulated by an amorphous ZrO 2 shell structure were significantly more active than the crystalline oxide encapsulated structures at low temperatures. Furthermore, CO DRIFTS studies showed that Pd redispersion occurred under CO oxidation reaction conditions and as a function of the oxide shell composition, being observed in Pd@TiO 2 systems only, with potential formation of smaller NPs and oxide-supported Pd clusters after reaction. This investigation demonstrated that metal oxide composition and (in some cases) crystallinity play major roles in catalyst activity for encapsulated catalytic systems.  more » « less
Award ID(s):
1900183 2311986
NSF-PAR ID:
10342744
Author(s) / Creator(s):
; ; ; ; ; ;
Date Published:
Journal Name:
Catalysis Science & Technology
Volume:
12
Issue:
5
ISSN:
2044-4753
Page Range / eLocation ID:
1476 to 1486
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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