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

27 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.

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

Access to Document

10.1016/j.apcata.2015.01.027

Cite this

@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",

month = apr,

day = "5",

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

language = "English",

volume = "495",

pages = "45--53",

}

TY - JOUR

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

UR - http://www.scopus.com/inward/record.url?scp=84923639926&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84923639926&partnerID=8YFLogxK

U2 - 10.1016/j.apcata.2015.01.027

DO - 10.1016/j.apcata.2015.01.027

M3 - Article

AN - SCOPUS:84923639926

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

Keywords

ASJC Scopus subject areas

Access to Document

Other files and links

Fingerprint

Cite this