Selectivity control of Cu promoted iron-based Fischer-Tropsch catalyst by tuning the oxidation state of Cu to mimic K

Venkat Ramana Rao Pendyala; Gary Jacobs; Muthu Kumaran Gnanamani; Yongfeng Hu; Aimee Maclennan; Burtron H. Davis

doi:10.1016/j.apcata.2015.01.027

Selectivity control of Cu promoted iron-based Fischer-Tropsch catalyst by tuning the oxidation state of Cu to mimic K

Venkat Ramana Rao Pendyala, Gary Jacobs, Muthu Kumaran Gnanamani, Yongfeng Hu, Aimee Maclennan, Burtron H. Davis

Center for Applied Energy Research (CAER)

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

28 Scopus citations

Abstract

The effect of activation gas on the Fischer-Tropsch synthesis (FTS) performance of copper and potassium promoted precipitated iron-based catalysts was investigated in an earlier study [Catal. Lett. 144 (2014) 1624-1635]. In that study, CO and syngas (H₂/CO = 0.7) activation methods were tested after varying the copper promoter loading (0, 2, and 5%, atomic ratios relative to iron). At similar CO conversion level, the selectivities for the CO-activated catalysts were identical for the various copper loaded catalysts, whereas for the syngas activated catalysts, light hydrocarbon (methane and C₂-C₄) selectivities decreased and higher hydrocarbon (C₅+) selectivities increased with increasing copper loading. To understand the reason for that behavior, the catalyst samples were characterized by XANES/EXAFS spectroscopy following each activation procedure before and after exposure to FTS conditions. Cu K-edge normalized XANES results indicate that for the syngas activated catalyst copper is present primarily in the Cu¹⁺ state, whereas for CO activated catalyst the copper is more reduced (greater fraction in the Cu⁰ state). The Cu¹⁺ in the syngas activated catalyst behaved like K¹⁺; therefore, the C₅+ selectivity was enhanced and light hydrocarbon selectivity was suppressed.

Original language	English
Pages (from-to)	45-53
Number of pages	9
Journal	Applied Catalysis A: General
Volume	495
DOIs	https://doi.org/10.1016/j.apcata.2015.01.027
State	Published - Apr 5 2015

Bibliographical note

Funding Information:
This work is supported by the University of Wyoming contract number 1001541-Davis and the Commonwealth of Kentucky . EXAFS/XANES described in this paper was performed in part at the Canadian Light Source, which is funded by the Canada Foundation for Innovation , the Natural Sciences and Engineering Research Council of Canada , the National Research Council Canada , the Canadian Institutes of Health Research , the Government of Saskatchewan , Western Economic Diversification Canada , and the University of Saskatchewan .

Publisher Copyright:
© 2015 Elsevier B.V. All rights reserved.

Funding

This work is supported by the University of Wyoming contract number 1001541-Davis and the Commonwealth of Kentucky . EXAFS/XANES described in this paper was performed in part at the Canadian Light Source, which is funded by the Canada Foundation for Innovation , the Natural Sciences and Engineering Research Council of Canada , the National Research Council Canada , the Canadian Institutes of Health Research , the Government of Saskatchewan , Western Economic Diversification Canada , and the University of Saskatchewan .

Funders	Funder number
Government of Saskatchewan
University of Wyoming	1001541-Davis
University of Saskatchewan
Canadian Institutes of Health Research
Natural Sciences and Engineering Research Council of Canada
Western Economic Diversification Canada
National Research Council Canada (NRCC)
Canada Foundation for Innovation

Keywords

Activation gas
Cu oxidation state
Fischer-Tropsch synthesis
Iron-based catalyst
Product selectivity
XANES/EXAFS

ASJC Scopus subject areas

Catalysis
Process Chemistry and Technology

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10.1016/j.apcata.2015.01.027

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@article{42d34b93d03b45589bcaff47b808e448,

title = "Selectivity control of Cu promoted iron-based Fischer-Tropsch catalyst by tuning the oxidation state of Cu to mimic K",

abstract = "The effect of activation gas on the Fischer-Tropsch synthesis (FTS) performance of copper and potassium promoted precipitated iron-based catalysts was investigated in an earlier study [Catal. Lett. 144 (2014) 1624-1635]. In that study, CO and syngas (H2/CO = 0.7) activation methods were tested after varying the copper promoter loading (0, 2, and 5\%, atomic ratios relative to iron). At similar CO conversion level, the selectivities for the CO-activated catalysts were identical for the various copper loaded catalysts, whereas for the syngas activated catalysts, light hydrocarbon (methane and C2-C4) selectivities decreased and higher hydrocarbon (C5+) selectivities increased with increasing copper loading. To understand the reason for that behavior, the catalyst samples were characterized by XANES/EXAFS spectroscopy following each activation procedure before and after exposure to FTS conditions. Cu K-edge normalized XANES results indicate that for the syngas activated catalyst copper is present primarily in the Cu1+ state, whereas for CO activated catalyst the copper is more reduced (greater fraction in the Cu0 state). The Cu1+ in the syngas activated catalyst behaved like K1+; therefore, the C5+ selectivity was enhanced and light hydrocarbon selectivity was suppressed.",

keywords = "Activation gas, Cu oxidation state, Fischer-Tropsch synthesis, Iron-based catalyst, Product selectivity, XANES/EXAFS",

author = "Pendyala, \{Venkat Ramana Rao\} and Gary Jacobs and Gnanamani, \{Muthu Kumaran\} and Yongfeng Hu and Aimee Maclennan and Davis, \{Burtron H.\}",

note = "Funding Information: This work is supported by the University of Wyoming contract number 1001541-Davis and the Commonwealth of Kentucky . EXAFS/XANES described in this paper was performed in part at the Canadian Light Source, which is funded by the Canada Foundation for Innovation , the Natural Sciences and Engineering Research Council of Canada , the National Research Council Canada , the Canadian Institutes of Health Research , the Government of Saskatchewan , Western Economic Diversification Canada , and the University of Saskatchewan . Publisher Copyright: {\textcopyright} 2015 Elsevier B.V. All rights reserved.",

year = "2015",

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doi = "10.1016/j.apcata.2015.01.027",

language = "English",

volume = "495",

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T1 - Selectivity control of Cu promoted iron-based Fischer-Tropsch catalyst by tuning the oxidation state of Cu to mimic K

AU - Pendyala, Venkat Ramana Rao

AU - Jacobs, Gary

AU - Gnanamani, Muthu Kumaran

AU - Hu, Yongfeng

AU - Maclennan, Aimee

AU - Davis, Burtron H.

N1 - Funding Information: This work is supported by the University of Wyoming contract number 1001541-Davis and the Commonwealth of Kentucky . EXAFS/XANES described in this paper was performed in part at the Canadian Light Source, which is funded by the Canada Foundation for Innovation , the Natural Sciences and Engineering Research Council of Canada , the National Research Council Canada , the Canadian Institutes of Health Research , the Government of Saskatchewan , Western Economic Diversification Canada , and the University of Saskatchewan . Publisher Copyright: © 2015 Elsevier B.V. All rights reserved.

PY - 2015/4/5

Y1 - 2015/4/5

N2 - The effect of activation gas on the Fischer-Tropsch synthesis (FTS) performance of copper and potassium promoted precipitated iron-based catalysts was investigated in an earlier study [Catal. Lett. 144 (2014) 1624-1635]. In that study, CO and syngas (H2/CO = 0.7) activation methods were tested after varying the copper promoter loading (0, 2, and 5%, atomic ratios relative to iron). At similar CO conversion level, the selectivities for the CO-activated catalysts were identical for the various copper loaded catalysts, whereas for the syngas activated catalysts, light hydrocarbon (methane and C2-C4) selectivities decreased and higher hydrocarbon (C5+) selectivities increased with increasing copper loading. To understand the reason for that behavior, the catalyst samples were characterized by XANES/EXAFS spectroscopy following each activation procedure before and after exposure to FTS conditions. Cu K-edge normalized XANES results indicate that for the syngas activated catalyst copper is present primarily in the Cu1+ state, whereas for CO activated catalyst the copper is more reduced (greater fraction in the Cu0 state). The Cu1+ in the syngas activated catalyst behaved like K1+; therefore, the C5+ selectivity was enhanced and light hydrocarbon selectivity was suppressed.

AB - The effect of activation gas on the Fischer-Tropsch synthesis (FTS) performance of copper and potassium promoted precipitated iron-based catalysts was investigated in an earlier study [Catal. Lett. 144 (2014) 1624-1635]. In that study, CO and syngas (H2/CO = 0.7) activation methods were tested after varying the copper promoter loading (0, 2, and 5%, atomic ratios relative to iron). At similar CO conversion level, the selectivities for the CO-activated catalysts were identical for the various copper loaded catalysts, whereas for the syngas activated catalysts, light hydrocarbon (methane and C2-C4) selectivities decreased and higher hydrocarbon (C5+) selectivities increased with increasing copper loading. To understand the reason for that behavior, the catalyst samples were characterized by XANES/EXAFS spectroscopy following each activation procedure before and after exposure to FTS conditions. Cu K-edge normalized XANES results indicate that for the syngas activated catalyst copper is present primarily in the Cu1+ state, whereas for CO activated catalyst the copper is more reduced (greater fraction in the Cu0 state). The Cu1+ in the syngas activated catalyst behaved like K1+; therefore, the C5+ selectivity was enhanced and light hydrocarbon selectivity was suppressed.

KW - Activation gas

KW - Cu oxidation state

KW - Fischer-Tropsch synthesis

KW - Iron-based catalyst

KW - Product selectivity

KW - XANES/EXAFS

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SN - 0926-860X

VL - 495

SP - 45

EP - 53

JO - Applied Catalysis A: General

JF - Applied Catalysis A: General

ER -

Selectivity control of Cu promoted iron-based Fischer-Tropsch catalyst by tuning the oxidation state of Cu to mimic K

Abstract

Bibliographical note

Funding

Keywords

ASJC Scopus subject areas

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