Activity and selectivity control by niobium for the preferential oxidation of co on pt supported catalysts

S. Guerrero; J. T. Miller; E. E. Wolf

doi:10.1016/j.apcata.2007.04.010

Activity and selectivity control by niobium for the preferential oxidation of co on pt supported catalysts

S. Guerrero, J. T. Miller, E. E. Wolf^*

^*Corresponding author for this work

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

38 Scopus citations

Abstract

The promotional effect of Nb on Pt supported on alumina or on niobia, was studied for the preferential oxidation of CO (PROX) in hydrogen. The results show a unique effect of Nb as a promoter to Pt. At low Nb loadings on Pt/alumina, the CO oxidation activity and selectivity are significantly increased. The CO selectivity is 100% at conversions up to about 60%. For Pt supported on Nb₂O₅, however, the CO oxidation activity is strongly suppressed with low CO conversion but high H₂ oxidation activity. Pt on niobia, therefore, is poorly selective for the PROX reaction, but is an active hydrogen oxidation catalyst, resistant to CO poisoning. For Pt supported on highly loaded Nb-alumina or Nb₂O₅, XPS indicate an increase in the Pt and Nb oxidation states. These surface changes also correlate with changes in the DRIFTS spectra suggesting that CO is more weakly adsorbed on Pt/Nb₂O₅ compared to Pt/Al₂O₃, or Pt/Nb-Al₂O₃.

Original language	English
Pages (from-to)	27-34
Number of pages	8
Journal	Applied Catalysis A: General
Volume	328
Issue number	1
DOIs	https://doi.org/10.1016/j.apcata.2007.04.010
State	Published - 31 Aug 2007
Externally published	Yes

Bibliographical note

Funding Information:
The support of this work by a grant from Companhia Brasileira de Metallurgia e Minerals, CBMM, and NSF CTS 01 38070 are gratefully acknowledged. We would also like to thank Prof. John Regalbuto for TEM analysis of Pt/Nb-Al 2 O 3 samples catalysts.

Keywords

Nb promoter
PROX reaction
Pt supported catalyst

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10.1016/j.apcata.2007.04.010

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title = "Activity and selectivity control by niobium for the preferential oxidation of co on pt supported catalysts",

abstract = "The promotional effect of Nb on Pt supported on alumina or on niobia, was studied for the preferential oxidation of CO (PROX) in hydrogen. The results show a unique effect of Nb as a promoter to Pt. At low Nb loadings on Pt/alumina, the CO oxidation activity and selectivity are significantly increased. The CO selectivity is 100% at conversions up to about 60%. For Pt supported on Nb2O5, however, the CO oxidation activity is strongly suppressed with low CO conversion but high H2 oxidation activity. Pt on niobia, therefore, is poorly selective for the PROX reaction, but is an active hydrogen oxidation catalyst, resistant to CO poisoning. For Pt supported on highly loaded Nb-alumina or Nb2O5, XPS indicate an increase in the Pt and Nb oxidation states. These surface changes also correlate with changes in the DRIFTS spectra suggesting that CO is more weakly adsorbed on Pt/Nb2O5 compared to Pt/Al2O3, or Pt/Nb-Al2O3.",

keywords = "Nb promoter, PROX reaction, Pt supported catalyst",

author = "S. Guerrero and Miller, {J. T.} and Wolf, {E. E.}",

note = "Funding Information: The support of this work by a grant from Companhia Brasileira de Metallurgia e Minerals, CBMM, and NSF CTS 01 38070 are gratefully acknowledged. We would also like to thank Prof. John Regalbuto for TEM analysis of Pt/Nb-Al 2 O 3 samples catalysts.",

year = "2007",

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doi = "10.1016/j.apcata.2007.04.010",

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AU - Guerrero, S.

AU - Miller, J. T.

AU - Wolf, E. E.

N1 - Funding Information: The support of this work by a grant from Companhia Brasileira de Metallurgia e Minerals, CBMM, and NSF CTS 01 38070 are gratefully acknowledged. We would also like to thank Prof. John Regalbuto for TEM analysis of Pt/Nb-Al 2 O 3 samples catalysts.

PY - 2007/8/31

Y1 - 2007/8/31

N2 - The promotional effect of Nb on Pt supported on alumina or on niobia, was studied for the preferential oxidation of CO (PROX) in hydrogen. The results show a unique effect of Nb as a promoter to Pt. At low Nb loadings on Pt/alumina, the CO oxidation activity and selectivity are significantly increased. The CO selectivity is 100% at conversions up to about 60%. For Pt supported on Nb2O5, however, the CO oxidation activity is strongly suppressed with low CO conversion but high H2 oxidation activity. Pt on niobia, therefore, is poorly selective for the PROX reaction, but is an active hydrogen oxidation catalyst, resistant to CO poisoning. For Pt supported on highly loaded Nb-alumina or Nb2O5, XPS indicate an increase in the Pt and Nb oxidation states. These surface changes also correlate with changes in the DRIFTS spectra suggesting that CO is more weakly adsorbed on Pt/Nb2O5 compared to Pt/Al2O3, or Pt/Nb-Al2O3.

AB - The promotional effect of Nb on Pt supported on alumina or on niobia, was studied for the preferential oxidation of CO (PROX) in hydrogen. The results show a unique effect of Nb as a promoter to Pt. At low Nb loadings on Pt/alumina, the CO oxidation activity and selectivity are significantly increased. The CO selectivity is 100% at conversions up to about 60%. For Pt supported on Nb2O5, however, the CO oxidation activity is strongly suppressed with low CO conversion but high H2 oxidation activity. Pt on niobia, therefore, is poorly selective for the PROX reaction, but is an active hydrogen oxidation catalyst, resistant to CO poisoning. For Pt supported on highly loaded Nb-alumina or Nb2O5, XPS indicate an increase in the Pt and Nb oxidation states. These surface changes also correlate with changes in the DRIFTS spectra suggesting that CO is more weakly adsorbed on Pt/Nb2O5 compared to Pt/Al2O3, or Pt/Nb-Al2O3.

KW - Nb promoter

KW - PROX reaction

KW - Pt supported catalyst

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Activity and selectivity control by niobium for the preferential oxidation of co on pt supported catalysts

Abstract

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Keywords

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