CO induced surface segregation as a means of improving surface composition and enhancing performance of CuPd bimetallic catalysts

Alan J. McCue; James A. Anderson

doi:10.1016/j.jcat.2015.06.002

CO induced surface segregation as a means of improving surface composition and enhancing performance of CuPd bimetallic catalysts

Alan J. McCue, James A. Anderson

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Abstract

A series of copper rich CuPd/Al2O3 catalysts were prepared and characterised by FTIR spectroscopy using CO as a probe molecule. After reduction, the surface composition was largely composed of Cu with evidence of a small concentration of isolated Pd atoms. It was found that CO induced surface segregation could be used to increase the surface Pd concentration and depending on the Cu:Pd ratio, the formation of Pd–Pd dimers was possible. Changes in surface composition were quantified and correlated with catalyst activity and selectivity for selective acetylene hydrogenation. For the catalyst with optimum Cu:Pd ratio (50:1), it was possible to use CO induced segregation to increase activity considerably (20 K temperature reduction to achieve 100% conversion) whilst only marginally affecting ethylene selectivity (≈5% decrease in ethylene selectivity). An estimate of the detection limit by FTIR of the minimum surface coverage of isolated Pd and Pd–Pd dimers is given.

Original language	English
Pages (from-to)	538-546
Number of pages	9
Journal	Journal of Catalysis
Volume	329
Early online date	25 Jul 2015
DOIs	https://doi.org/10.1016/j.jcat.2015.06.002
Publication status	Published - Sept 2015

Bibliographical note

Date of Acceptance: 01/06/2015

We thank the University of Aberdeen for financial support and A.I. McNab (University of Aberdeen) for discussions involving the calculation of surface sites.

Keywords

copper
palladium
FTIR spectroscopy
selective hydrogenation
surface segregation

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CO induced surface segregation as a means of improving surface composition and enhancing performance of CuPd bimetallic catalysts
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Cite this

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title = "CO induced surface segregation as a means of improving surface composition and enhancing performance of CuPd bimetallic catalysts",

abstract = "A series of copper rich CuPd/Al2O3 catalysts were prepared and characterised by FTIR spectroscopy using CO as a probe molecule. After reduction, the surface composition was largely composed of Cu with evidence of a small concentration of isolated Pd atoms. It was found that CO induced surface segregation could be used to increase the surface Pd concentration and depending on the Cu:Pd ratio, the formation of Pd–Pd dimers was possible. Changes in surface composition were quantified and correlated with catalyst activity and selectivity for selective acetylene hydrogenation. For the catalyst with optimum Cu:Pd ratio (50:1), it was possible to use CO induced segregation to increase activity considerably (20 K temperature reduction to achieve 100% conversion) whilst only marginally affecting ethylene selectivity (≈5% decrease in ethylene selectivity). An estimate of the detection limit by FTIR of the minimum surface coverage of isolated Pd and Pd–Pd dimers is given.",

keywords = "copper, palladium, FTIR spectroscopy, selective hydrogenation, surface segregation",

author = "McCue, {Alan J.} and Anderson, {James A.}",

note = "Date of Acceptance: 01/06/2015 We thank the University of Aberdeen for financial support and A.I. McNab (University of Aberdeen) for discussions involving the calculation of surface sites.",

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doi = "10.1016/j.jcat.2015.06.002",

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TY - JOUR

T1 - CO induced surface segregation as a means of improving surface composition and enhancing performance of CuPd bimetallic catalysts

AU - McCue, Alan J.

AU - Anderson, James A.

N1 - Date of Acceptance: 01/06/2015 We thank the University of Aberdeen for financial support and A.I. McNab (University of Aberdeen) for discussions involving the calculation of surface sites.

PY - 2015/9

Y1 - 2015/9

N2 - A series of copper rich CuPd/Al2O3 catalysts were prepared and characterised by FTIR spectroscopy using CO as a probe molecule. After reduction, the surface composition was largely composed of Cu with evidence of a small concentration of isolated Pd atoms. It was found that CO induced surface segregation could be used to increase the surface Pd concentration and depending on the Cu:Pd ratio, the formation of Pd–Pd dimers was possible. Changes in surface composition were quantified and correlated with catalyst activity and selectivity for selective acetylene hydrogenation. For the catalyst with optimum Cu:Pd ratio (50:1), it was possible to use CO induced segregation to increase activity considerably (20 K temperature reduction to achieve 100% conversion) whilst only marginally affecting ethylene selectivity (≈5% decrease in ethylene selectivity). An estimate of the detection limit by FTIR of the minimum surface coverage of isolated Pd and Pd–Pd dimers is given.

AB - A series of copper rich CuPd/Al2O3 catalysts were prepared and characterised by FTIR spectroscopy using CO as a probe molecule. After reduction, the surface composition was largely composed of Cu with evidence of a small concentration of isolated Pd atoms. It was found that CO induced surface segregation could be used to increase the surface Pd concentration and depending on the Cu:Pd ratio, the formation of Pd–Pd dimers was possible. Changes in surface composition were quantified and correlated with catalyst activity and selectivity for selective acetylene hydrogenation. For the catalyst with optimum Cu:Pd ratio (50:1), it was possible to use CO induced segregation to increase activity considerably (20 K temperature reduction to achieve 100% conversion) whilst only marginally affecting ethylene selectivity (≈5% decrease in ethylene selectivity). An estimate of the detection limit by FTIR of the minimum surface coverage of isolated Pd and Pd–Pd dimers is given.

KW - copper

KW - palladium

KW - FTIR spectroscopy

KW - selective hydrogenation

KW - surface segregation

U2 - 10.1016/j.jcat.2015.06.002

DO - 10.1016/j.jcat.2015.06.002

M3 - Article

SN - 0021-9517

VL - 329

SP - 538

EP - 546

JO - Journal of Catalysis

JF - Journal of Catalysis

ER -

CO induced surface segregation as a means of improving surface composition and enhancing performance of CuPd bimetallic catalysts

Abstract

Bibliographical note

Keywords

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