In situ studies of titania-supported Au shell-Pd core nanoparticles for the selective aerobic oxidation of crotyl alcohol

Adam F. Lee; Christine V. Ellis; Karen Wilson; Nicole S. Hondow

doi:10.1016/j.cattod.2010.04.032

In situ studies of titania-supported Au shell-Pd core nanoparticles for the selective aerobic oxidation of crotyl alcohol

Adam F. Lee, Christine V. Ellis, Karen Wilson, Nicole S. Hondow

Research output: Contribution to journal › Article › peer-review

Abstract

The thermal evolution of titania-supported Au shell–Pd core bimetallic nanoparticles, prepared via colloidal routes, has been investigated by in situ XPS, DRIFTS, EXAFS and XRD and ex situ HRTEM. As-prepared nanoparticles are terminated by a thin (∼5 layer) Au shell, encapsulating approximately 20 nm diameter cuboctahedral palladium cores, with the ensemble stabilised by citrate ligands. The net gold composition was 40 atom%. Annealing in vacuo or under inert atmosphere rapidly pyrolyses the citrate ligands, but induces only limited Au/Pd intermixing and particle growth <300 °C. Higher temperatures promote more dramatic alloying, accompanied by significant sintering and surface roughening. These changes are mirrored by the nanoparticle catalysed liquid phase selective aerobic oxidation of crotyl alcohol to crotonaldehyde; palladium surface segregation enhances both activity and selectivity, with the most active surface alloy attainable containing ∼40 atom% Au.

Original language	English
Pages (from-to)	243-249
Number of pages	7
Journal	Catalysis Today
Volume	157
Issue number	1-4
Early online date	23 May 2010
DOIs	https://doi.org/10.1016/j.cattod.2010.04.032
Publication status	Published - 17 Nov 2010
Event	6th World Congress on Oxidation Catalysis - Lille, France Duration: 5 Jul 2009 → 10 Jul 2009

Bibliographical note

We thank the Engineering and Physical Sciences Research Council for financial support (EP/E046754/1 and EP/G007594/1) and the award of a Leadership Fellowship (A.F.L.) and studentship (C.V.E.). Electron microscopy access was provided through the Leeds EPSRC Nanoscience and Nanotechnology Research Equipment Facility (LENNF) (EP/F056311/1). We also thank Syngenta for additional studentship support and Mr. L. Dingwall (York Chemistry) and Dr. I. Harvey for assistance with DRIFTS and EXAFS measurements, respectively.

Keywords

bimetallic
gold
palladium
XPS
oxidation
in situ

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abstract = "The thermal evolution of titania-supported Au shell–Pd core bimetallic nanoparticles, prepared via colloidal routes, has been investigated by in situ XPS, DRIFTS, EXAFS and XRD and ex situ HRTEM. As-prepared nanoparticles are terminated by a thin (∼5 layer) Au shell, encapsulating approximately 20 nm diameter cuboctahedral palladium cores, with the ensemble stabilised by citrate ligands. The net gold composition was 40 atom%. Annealing in vacuo or under inert atmosphere rapidly pyrolyses the citrate ligands, but induces only limited Au/Pd intermixing and particle growth <300 °C. Higher temperatures promote more dramatic alloying, accompanied by significant sintering and surface roughening. These changes are mirrored by the nanoparticle catalysed liquid phase selective aerobic oxidation of crotyl alcohol to crotonaldehyde; palladium surface segregation enhances both activity and selectivity, with the most active surface alloy attainable containing ∼40 atom% Au.",

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In situ studies of titania-supported Au shell-Pd core nanoparticles for the selective aerobic oxidation of crotyl alcohol

Abstract

Bibliographical note

Keywords

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