Tunability of propane conversion over alumina supported Pt and Rh catalysts

William C. Chueh; Zongping Shao; Sossina M. Haile

doi:10.1007/s11244-007-9012-9

Tunability of propane conversion over alumina supported Pt and Rh catalysts

William C. Chueh, Zongping Shao, Sossina M. Haile^*

^*Corresponding author for this work

Materials Science and Engineering

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

11 Scopus citations

Abstract

Propane conversion over alumina supported Pt and Rh (1 wt% metals loading) was examined under fuel rich conditions (C₃H₈:O₂:He = 1:2.25:9) over the temperature range 450-650 °C. Morphological characteristics of the catalyst materials were varied by calcining at selected temperatures between 500 and 1,200 °C. X-ray diffraction and BET analysis showed the treatment generated catalyts metals with particle sizes in the range of <10 to >500 nm, and support surface areas in the range of 20-240 m²/g. Remarkably, both Rh and Pt yielded product compositions close to equilibrium values (with high H₂ and CO selectivity, complete oxygen conversion and almost complete propane conversion) so long as the metal particle size was sufficiently low, <≈10-15 nm. In cases where the particle size was large, primarily complete oxidation rather than partial oxidation products were observed, along with unreacted C₃H₈, indicative of a direct oxidation pathway in which gas-phase CO and H₂ are not present as intermediate species. It is proposed that the high resistance of Rh to coarsening is largely responsible for the observation of a higher selectivity of this material for syngas products when prepared by procedures similar to those for Pt. Overall, the tunability of the product composition obtained over Rh and Pt via processing steps has direct significance for the incorporation of such catalyts into the anodes of solid oxide fuel cells.

Original language	English (US)
Pages (from-to)	402-411
Number of pages	10
Journal	Topics in Catalysis
Volume	46
Issue number	3-4
DOIs	https://doi.org/10.1007/s11244-007-9012-9
State	Published - Dec 2007

Funding

Acknowledgements The authors gratefully acknowledge the assistance of Carol Garland (Caltech) in obtaining the TEM images and Dr. David G. Goodwin (Caltech) for insightful discussions. This study was funded by DARPA, Microsystems Technology Office and by ONR, Office of Electrochemical Power Science and Technology. Additional support was provided by the National Science Foundation (DMR-0080065) via Caltech\u2019s Center for the Science and Engineering of Materials, an NSF Materials Research Science and Engineering Center (MRSEC).

Keywords

Mental particle coarsening
Propane partial oxidation
Pt/AlO
Rh/AlO
Sofc anode catalyst

ASJC Scopus subject areas

Catalysis
General Chemistry

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10.1007/s11244-007-9012-9

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@article{b297ab3cd0ef40da89e43ce1273c188d,

title = "Tunability of propane conversion over alumina supported Pt and Rh catalysts",

abstract = "Propane conversion over alumina supported Pt and Rh (1 wt% metals loading) was examined under fuel rich conditions (C3H8:O2:He = 1:2.25:9) over the temperature range 450-650 °C. Morphological characteristics of the catalyst materials were varied by calcining at selected temperatures between 500 and 1,200 °C. X-ray diffraction and BET analysis showed the treatment generated catalyts metals with particle sizes in the range of <10 to >500 nm, and support surface areas in the range of 20-240 m2/g. Remarkably, both Rh and Pt yielded product compositions close to equilibrium values (with high H2 and CO selectivity, complete oxygen conversion and almost complete propane conversion) so long as the metal particle size was sufficiently low, <≈10-15 nm. In cases where the particle size was large, primarily complete oxidation rather than partial oxidation products were observed, along with unreacted C3H8, indicative of a direct oxidation pathway in which gas-phase CO and H2 are not present as intermediate species. It is proposed that the high resistance of Rh to coarsening is largely responsible for the observation of a higher selectivity of this material for syngas products when prepared by procedures similar to those for Pt. Overall, the tunability of the product composition obtained over Rh and Pt via processing steps has direct significance for the incorporation of such catalyts into the anodes of solid oxide fuel cells.",

keywords = "Mental particle coarsening, Propane partial oxidation, Pt/AlO, Rh/AlO, Sofc anode catalyst",

author = "Chueh, {William C.} and Zongping Shao and Haile, {Sossina M.}",

note = "Funding Information: Acknowledgements The authors gratefully acknowledge the assistance of Carol Garland (Caltech) in obtaining the TEM images and Dr. David G. Goodwin (Caltech) for insightful discussions. This study was funded by DARPA, Microsystems Technology Office and by ONR, Office of Electrochemical Power Science and Technology. Additional support was provided by the National Science Foundation (DMR-0080065) via Caltech{\textquoteright}s Center for the Science and Engineering of Materials, an NSF Materials Research Science and Engineering Center (MRSEC).",

year = "2007",

month = dec,

doi = "10.1007/s11244-007-9012-9",

language = "English (US)",

volume = "46",

pages = "402--411",

journal = "Topics in Catalysis",

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T1 - Tunability of propane conversion over alumina supported Pt and Rh catalysts

AU - Chueh, William C.

AU - Shao, Zongping

AU - Haile, Sossina M.

N1 - Funding Information: Acknowledgements The authors gratefully acknowledge the assistance of Carol Garland (Caltech) in obtaining the TEM images and Dr. David G. Goodwin (Caltech) for insightful discussions. This study was funded by DARPA, Microsystems Technology Office and by ONR, Office of Electrochemical Power Science and Technology. Additional support was provided by the National Science Foundation (DMR-0080065) via Caltech’s Center for the Science and Engineering of Materials, an NSF Materials Research Science and Engineering Center (MRSEC).

PY - 2007/12

Y1 - 2007/12

N2 - Propane conversion over alumina supported Pt and Rh (1 wt% metals loading) was examined under fuel rich conditions (C3H8:O2:He = 1:2.25:9) over the temperature range 450-650 °C. Morphological characteristics of the catalyst materials were varied by calcining at selected temperatures between 500 and 1,200 °C. X-ray diffraction and BET analysis showed the treatment generated catalyts metals with particle sizes in the range of <10 to >500 nm, and support surface areas in the range of 20-240 m2/g. Remarkably, both Rh and Pt yielded product compositions close to equilibrium values (with high H2 and CO selectivity, complete oxygen conversion and almost complete propane conversion) so long as the metal particle size was sufficiently low, <≈10-15 nm. In cases where the particle size was large, primarily complete oxidation rather than partial oxidation products were observed, along with unreacted C3H8, indicative of a direct oxidation pathway in which gas-phase CO and H2 are not present as intermediate species. It is proposed that the high resistance of Rh to coarsening is largely responsible for the observation of a higher selectivity of this material for syngas products when prepared by procedures similar to those for Pt. Overall, the tunability of the product composition obtained over Rh and Pt via processing steps has direct significance for the incorporation of such catalyts into the anodes of solid oxide fuel cells.

AB - Propane conversion over alumina supported Pt and Rh (1 wt% metals loading) was examined under fuel rich conditions (C3H8:O2:He = 1:2.25:9) over the temperature range 450-650 °C. Morphological characteristics of the catalyst materials were varied by calcining at selected temperatures between 500 and 1,200 °C. X-ray diffraction and BET analysis showed the treatment generated catalyts metals with particle sizes in the range of <10 to >500 nm, and support surface areas in the range of 20-240 m2/g. Remarkably, both Rh and Pt yielded product compositions close to equilibrium values (with high H2 and CO selectivity, complete oxygen conversion and almost complete propane conversion) so long as the metal particle size was sufficiently low, <≈10-15 nm. In cases where the particle size was large, primarily complete oxidation rather than partial oxidation products were observed, along with unreacted C3H8, indicative of a direct oxidation pathway in which gas-phase CO and H2 are not present as intermediate species. It is proposed that the high resistance of Rh to coarsening is largely responsible for the observation of a higher selectivity of this material for syngas products when prepared by procedures similar to those for Pt. Overall, the tunability of the product composition obtained over Rh and Pt via processing steps has direct significance for the incorporation of such catalyts into the anodes of solid oxide fuel cells.

KW - Mental particle coarsening

KW - Propane partial oxidation

KW - Pt/AlO

KW - Rh/AlO

KW - Sofc anode catalyst

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JF - Topics in Catalysis

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ER -

Tunability of propane conversion over alumina supported Pt and Rh catalysts

Abstract

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Keywords

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