Improved CO oxidation activity in the presence and absence of hydrogen over cluster-derived PtFe/SiO 2 catalysts

Attilio Siani; Burjor Captain; Oleg S. Alexeev; Eirini Stafyla; Ana B. Hungria; Paul A. Midgley; John Meurig Thomas; Richard D. Adams; Michael D. Amiridis

doi:10.1021/la053476a

Improved CO oxidation activity in the presence and absence of hydrogen over cluster-derived PtFe/SiO ₂ catalysts

Attilio Siani, Burjor Captain, Oleg S. Alexeev, Eirini Stafyla, Ana B. Hungria, Paul A. Midgley, John Meurig Thomas, Richard D. Adams, Michael D. Amiridis

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

68 Scopus citations

Abstract

The catalytic performance of cluster-derived PtFe/SiO ₂ bimetallic catalysts for the oxidation of CO has been examined in the absence and presence of _H2 (PROX) and compared to that of Pt/SiO ₂- PtFe ₂/SiO ₂ and Pt;Fe ₂/SiO ₂ samples were prepared from PtFe ₂(COD)(CO) ₈ and Pt ₅Fe ₂(COD) ₂(CO) ₁₂ organometallic cluster precursors, respectively. FTIR data indicate that both clusters can be deposited intact on the SiO ₂ support. The clusters remained weakly bonded to the SiO ₂ surface and could be extracted with CH ₂Cl ₂ without any significant changes in their structure. Subsequent heating in H ₂ led to complete decarbonylation of the supported clusters at approximately 350°C and the formation of Pt-Fe nanoparticles with sizes in the 1-2 nm range, as indicated by HRTEM imaging. A few larger nanoparticles enriched in Pt were also observed, indicating that a small fraction of the deposited clusters were segregated to the individual components following the hydrogen treatment. A higher degree of metal dispersion and more homogeneous mixing of the two metals were observed during HRTEM/XEDS analysis with the cluster-derived samples, as compared to a PtFe/SiO ₂ catalyst prepared through a conventional impregnation route. Furthermore, the cluster-derived PtFe ₂/SiO ₂ and Pt ₅Fe ₂/SiO ₂ samples were more active than Pt/SiO ₂ and the conventionally prepared PtFe/SiO ₂ sample for the oxidation of CO in air. However, substantial deactivation was also observed, indicating that the properties of the Pt-Fe bimetallic sites in the cluster-derived samples were altered by exposure to the reactants. The Pt ₅Fe ₂/SiO ₂ sample was also more active than Pt/SiO ₂ for PROX with a selectivity of approximately 92% at 50°C. In this case, the deactivation with time on stream was substantially slower, indicating that the highly reducing environment under the PROX conditions helps maintain the properties of the active Pt-Fe bimetallic sites.

Original language	English (US)
Pages (from-to)	5160-5167
Number of pages	8
Journal	Langmuir
Volume	22
Issue number	11
DOIs	https://doi.org/10.1021/la053476a
State	Published - May 23 2006
Externally published	Yes

ASJC Scopus subject areas

Materials Science(all)
Condensed Matter Physics
Surfaces and Interfaces
Spectroscopy
Electrochemistry

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Improved CO oxidation activity in the presence and absence of hydrogen over cluster-derived PtFe/SiO ₂ catalysts. / Siani, Attilio; Captain, Burjor; Alexeev, Oleg S.; Stafyla, Eirini; Hungria, Ana B.; Midgley, Paul A.; Thomas, John Meurig; Adams, Richard D.; Amiridis, Michael D.

In: Langmuir, Vol. 22, No. 11, 23.05.2006, p. 5160-5167.

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

@article{a83c0e10c5f94d62b7d51e3b01d51ba8,

title = "Improved CO oxidation activity in the presence and absence of hydrogen over cluster-derived PtFe/SiO 2 catalysts",

abstract = "The catalytic performance of cluster-derived PtFe/SiO 2 bimetallic catalysts for the oxidation of CO has been examined in the absence and presence of H2 (PROX) and compared to that of Pt/SiO 2- PtFe 2/SiO 2 and Pt;Fe 2/SiO 2 samples were prepared from PtFe 2(COD)(CO) 8 and Pt 5Fe 2(COD) 2(CO) 12 organometallic cluster precursors, respectively. FTIR data indicate that both clusters can be deposited intact on the SiO 2 support. The clusters remained weakly bonded to the SiO 2 surface and could be extracted with CH 2Cl 2 without any significant changes in their structure. Subsequent heating in H 2 led to complete decarbonylation of the supported clusters at approximately 350°C and the formation of Pt-Fe nanoparticles with sizes in the 1-2 nm range, as indicated by HRTEM imaging. A few larger nanoparticles enriched in Pt were also observed, indicating that a small fraction of the deposited clusters were segregated to the individual components following the hydrogen treatment. A higher degree of metal dispersion and more homogeneous mixing of the two metals were observed during HRTEM/XEDS analysis with the cluster-derived samples, as compared to a PtFe/SiO 2 catalyst prepared through a conventional impregnation route. Furthermore, the cluster-derived PtFe 2/SiO 2 and Pt 5Fe 2/SiO 2 samples were more active than Pt/SiO 2 and the conventionally prepared PtFe/SiO 2 sample for the oxidation of CO in air. However, substantial deactivation was also observed, indicating that the properties of the Pt-Fe bimetallic sites in the cluster-derived samples were altered by exposure to the reactants. The Pt 5Fe 2/SiO 2 sample was also more active than Pt/SiO 2 for PROX with a selectivity of approximately 92% at 50°C. In this case, the deactivation with time on stream was substantially slower, indicating that the highly reducing environment under the PROX conditions helps maintain the properties of the active Pt-Fe bimetallic sites.",

author = "Attilio Siani and Burjor Captain and Alexeev, {Oleg S.} and Eirini Stafyla and Hungria, {Ana B.} and Midgley, {Paul A.} and Thomas, {John Meurig} and Adams, {Richard D.} and Amiridis, {Michael D.}",

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doi = "10.1021/la053476a",

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T1 - Improved CO oxidation activity in the presence and absence of hydrogen over cluster-derived PtFe/SiO 2 catalysts

AU - Siani, Attilio

AU - Captain, Burjor

AU - Alexeev, Oleg S.

AU - Stafyla, Eirini

AU - Hungria, Ana B.

AU - Midgley, Paul A.

AU - Thomas, John Meurig

AU - Adams, Richard D.

AU - Amiridis, Michael D.

PY - 2006/5/23

Y1 - 2006/5/23

N2 - The catalytic performance of cluster-derived PtFe/SiO 2 bimetallic catalysts for the oxidation of CO has been examined in the absence and presence of H2 (PROX) and compared to that of Pt/SiO 2- PtFe 2/SiO 2 and Pt;Fe 2/SiO 2 samples were prepared from PtFe 2(COD)(CO) 8 and Pt 5Fe 2(COD) 2(CO) 12 organometallic cluster precursors, respectively. FTIR data indicate that both clusters can be deposited intact on the SiO 2 support. The clusters remained weakly bonded to the SiO 2 surface and could be extracted with CH 2Cl 2 without any significant changes in their structure. Subsequent heating in H 2 led to complete decarbonylation of the supported clusters at approximately 350°C and the formation of Pt-Fe nanoparticles with sizes in the 1-2 nm range, as indicated by HRTEM imaging. A few larger nanoparticles enriched in Pt were also observed, indicating that a small fraction of the deposited clusters were segregated to the individual components following the hydrogen treatment. A higher degree of metal dispersion and more homogeneous mixing of the two metals were observed during HRTEM/XEDS analysis with the cluster-derived samples, as compared to a PtFe/SiO 2 catalyst prepared through a conventional impregnation route. Furthermore, the cluster-derived PtFe 2/SiO 2 and Pt 5Fe 2/SiO 2 samples were more active than Pt/SiO 2 and the conventionally prepared PtFe/SiO 2 sample for the oxidation of CO in air. However, substantial deactivation was also observed, indicating that the properties of the Pt-Fe bimetallic sites in the cluster-derived samples were altered by exposure to the reactants. The Pt 5Fe 2/SiO 2 sample was also more active than Pt/SiO 2 for PROX with a selectivity of approximately 92% at 50°C. In this case, the deactivation with time on stream was substantially slower, indicating that the highly reducing environment under the PROX conditions helps maintain the properties of the active Pt-Fe bimetallic sites.

AB - The catalytic performance of cluster-derived PtFe/SiO 2 bimetallic catalysts for the oxidation of CO has been examined in the absence and presence of H2 (PROX) and compared to that of Pt/SiO 2- PtFe 2/SiO 2 and Pt;Fe 2/SiO 2 samples were prepared from PtFe 2(COD)(CO) 8 and Pt 5Fe 2(COD) 2(CO) 12 organometallic cluster precursors, respectively. FTIR data indicate that both clusters can be deposited intact on the SiO 2 support. The clusters remained weakly bonded to the SiO 2 surface and could be extracted with CH 2Cl 2 without any significant changes in their structure. Subsequent heating in H 2 led to complete decarbonylation of the supported clusters at approximately 350°C and the formation of Pt-Fe nanoparticles with sizes in the 1-2 nm range, as indicated by HRTEM imaging. A few larger nanoparticles enriched in Pt were also observed, indicating that a small fraction of the deposited clusters were segregated to the individual components following the hydrogen treatment. A higher degree of metal dispersion and more homogeneous mixing of the two metals were observed during HRTEM/XEDS analysis with the cluster-derived samples, as compared to a PtFe/SiO 2 catalyst prepared through a conventional impregnation route. Furthermore, the cluster-derived PtFe 2/SiO 2 and Pt 5Fe 2/SiO 2 samples were more active than Pt/SiO 2 and the conventionally prepared PtFe/SiO 2 sample for the oxidation of CO in air. However, substantial deactivation was also observed, indicating that the properties of the Pt-Fe bimetallic sites in the cluster-derived samples were altered by exposure to the reactants. The Pt 5Fe 2/SiO 2 sample was also more active than Pt/SiO 2 for PROX with a selectivity of approximately 92% at 50°C. In this case, the deactivation with time on stream was substantially slower, indicating that the highly reducing environment under the PROX conditions helps maintain the properties of the active Pt-Fe bimetallic sites.

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