Structural and electronic promotion with alkali cations of silica-supported Fe(III) sites for alkane oxidation

Dario Prieto-Centurion; Andrew M. Boston; Justin M. Notestein

doi:10.1016/j.jcat.2012.09.004

Structural and electronic promotion with alkali cations of silica-supported Fe(III) sites for alkane oxidation

Dario Prieto-Centurion, Andrew M. Boston, Justin M. Notestein^*

^*Corresponding author for this work

Chemical and Biological Engineering

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

21 Scopus citations

Abstract

Promoters and precursors can control oxide phase, dispersion, and per-site reactivity of supported oxide catalysts. Previously, dispersed FeOx-SiO ₂ resulted from Fe³⁺ ethylenediaminetetraacetate (FeEDTA^-) precursors, with NaFeEDTA giving enhanced dispersion and oxidation rates vs. NH₄FeEDTA. Here, catalysts were synthesized by sequential alkali deposition and Fe³⁺ impregnation. At up to 0.9 Fe nm^-2 from NH₄FeEDTA and equimolar alkali, UV-visible and H₂ TPR were consistent with isolated Fe³⁺ and small FeOx clusters. Omitting alkali, using Fe(NO₃)₃, or using Fe/alkali >1 gave evidence of larger agglomerates. For Fe/alkali ≤1 on non-porous SiO₂, initial turnover frequencies in adamantane oxidation using H₂O₂ were independent of surface density. TOF increased as 6.3, 8.8, 15.4, and 20.9 (±0.3) ks^-1 for Li ⁺, Na⁺, K⁺, and Cs⁺, respectively, increasingly linearly with decreasing electronegativity. These results give a synthesis-structure-function taxonomy with alkali as an electronic and structural promoter of dispersed FeOx species for alkane selective oxidation.

Original language	English (US)
Pages (from-to)	77-85
Number of pages	9
Journal	Journal of Catalysis
Volume	296
DOIs	https://doi.org/10.1016/j.jcat.2012.09.004
State	Published - Dec 2012

Funding

J.M.N. acknowledges support from U.S. Department of Energy-Office of Basic Energy Sciences grant DE-SC0006718, Northwestern University, and a 3M Non-Tenured Faculty Grant. DPC acknowledges the support of Toyota Motor Engineering, Inc. and thanks Dr. Christian Canlas, Pria Young, and Todd Eaton for the helpful discussions. Portions of this work were performed with the valuable help of Dr. Qing Ma at the DuPont-Northwestern-Dow Collaborative Access Team (DND-CAT) located at Sector 5 of the Advanced Photon Source (APS). DND-CAT is supported by E.I. DuPont de Nemours & Co., The Dow Chemical Company and Northwestern University. Use of the APS, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357.

Keywords

Alkali promoters
EDTA ligand
High dispersion
Single-site catalyst
Supported oxide

ASJC Scopus subject areas

Catalysis
Physical and Theoretical Chemistry

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10.1016/j.jcat.2012.09.004

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@article{b7d2bd437b974ed6985ab8c44ba70937,

title = "Structural and electronic promotion with alkali cations of silica-supported Fe(III) sites for alkane oxidation",

abstract = "Promoters and precursors can control oxide phase, dispersion, and per-site reactivity of supported oxide catalysts. Previously, dispersed FeOx-SiO 2 resulted from Fe3+ ethylenediaminetetraacetate (FeEDTA-) precursors, with NaFeEDTA giving enhanced dispersion and oxidation rates vs. NH4FeEDTA. Here, catalysts were synthesized by sequential alkali deposition and Fe3+ impregnation. At up to 0.9 Fe nm-2 from NH4FeEDTA and equimolar alkali, UV-visible and H2 TPR were consistent with isolated Fe3+ and small FeOx clusters. Omitting alkali, using Fe(NO3)3, or using Fe/alkali >1 gave evidence of larger agglomerates. For Fe/alkali ≤1 on non-porous SiO2, initial turnover frequencies in adamantane oxidation using H2O2 were independent of surface density. TOF increased as 6.3, 8.8, 15.4, and 20.9 (±0.3) ks-1 for Li +, Na+, K+, and Cs+, respectively, increasingly linearly with decreasing electronegativity. These results give a synthesis-structure-function taxonomy with alkali as an electronic and structural promoter of dispersed FeOx species for alkane selective oxidation.",

keywords = "Alkali promoters, EDTA ligand, High dispersion, Single-site catalyst, Supported oxide",

author = "Dario Prieto-Centurion and Boston, {Andrew M.} and Notestein, {Justin M.}",

note = "Funding Information: J.M.N. acknowledges support from U.S. Department of Energy-Office of Basic Energy Sciences grant DE-SC0006718, Northwestern University, and a 3M Non-Tenured Faculty Grant. DPC acknowledges the support of Toyota Motor Engineering, Inc. and thanks Dr. Christian Canlas, Pria Young, and Todd Eaton for the helpful discussions. Portions of this work were performed with the valuable help of Dr. Qing Ma at the DuPont-Northwestern-Dow Collaborative Access Team (DND-CAT) located at Sector 5 of the Advanced Photon Source (APS). DND-CAT is supported by E.I. DuPont de Nemours & Co., The Dow Chemical Company and Northwestern University. Use of the APS, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357. ",

year = "2012",

month = dec,

doi = "10.1016/j.jcat.2012.09.004",

language = "English (US)",

volume = "296",

pages = "77--85",

journal = "Journal of Catalysis",

issn = "0021-9517",

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T1 - Structural and electronic promotion with alkali cations of silica-supported Fe(III) sites for alkane oxidation

AU - Prieto-Centurion, Dario

AU - Boston, Andrew M.

AU - Notestein, Justin M.

N1 - Funding Information: J.M.N. acknowledges support from U.S. Department of Energy-Office of Basic Energy Sciences grant DE-SC0006718, Northwestern University, and a 3M Non-Tenured Faculty Grant. DPC acknowledges the support of Toyota Motor Engineering, Inc. and thanks Dr. Christian Canlas, Pria Young, and Todd Eaton for the helpful discussions. Portions of this work were performed with the valuable help of Dr. Qing Ma at the DuPont-Northwestern-Dow Collaborative Access Team (DND-CAT) located at Sector 5 of the Advanced Photon Source (APS). DND-CAT is supported by E.I. DuPont de Nemours & Co., The Dow Chemical Company and Northwestern University. Use of the APS, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357.

PY - 2012/12

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N2 - Promoters and precursors can control oxide phase, dispersion, and per-site reactivity of supported oxide catalysts. Previously, dispersed FeOx-SiO 2 resulted from Fe3+ ethylenediaminetetraacetate (FeEDTA-) precursors, with NaFeEDTA giving enhanced dispersion and oxidation rates vs. NH4FeEDTA. Here, catalysts were synthesized by sequential alkali deposition and Fe3+ impregnation. At up to 0.9 Fe nm-2 from NH4FeEDTA and equimolar alkali, UV-visible and H2 TPR were consistent with isolated Fe3+ and small FeOx clusters. Omitting alkali, using Fe(NO3)3, or using Fe/alkali >1 gave evidence of larger agglomerates. For Fe/alkali ≤1 on non-porous SiO2, initial turnover frequencies in adamantane oxidation using H2O2 were independent of surface density. TOF increased as 6.3, 8.8, 15.4, and 20.9 (±0.3) ks-1 for Li +, Na+, K+, and Cs+, respectively, increasingly linearly with decreasing electronegativity. These results give a synthesis-structure-function taxonomy with alkali as an electronic and structural promoter of dispersed FeOx species for alkane selective oxidation.

AB - Promoters and precursors can control oxide phase, dispersion, and per-site reactivity of supported oxide catalysts. Previously, dispersed FeOx-SiO 2 resulted from Fe3+ ethylenediaminetetraacetate (FeEDTA-) precursors, with NaFeEDTA giving enhanced dispersion and oxidation rates vs. NH4FeEDTA. Here, catalysts were synthesized by sequential alkali deposition and Fe3+ impregnation. At up to 0.9 Fe nm-2 from NH4FeEDTA and equimolar alkali, UV-visible and H2 TPR were consistent with isolated Fe3+ and small FeOx clusters. Omitting alkali, using Fe(NO3)3, or using Fe/alkali >1 gave evidence of larger agglomerates. For Fe/alkali ≤1 on non-porous SiO2, initial turnover frequencies in adamantane oxidation using H2O2 were independent of surface density. TOF increased as 6.3, 8.8, 15.4, and 20.9 (±0.3) ks-1 for Li +, Na+, K+, and Cs+, respectively, increasingly linearly with decreasing electronegativity. These results give a synthesis-structure-function taxonomy with alkali as an electronic and structural promoter of dispersed FeOx species for alkane selective oxidation.

KW - Alkali promoters

KW - EDTA ligand

KW - High dispersion

KW - Single-site catalyst

KW - Supported oxide

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JO - Journal of Catalysis

JF - Journal of Catalysis

ER -

Structural and electronic promotion with alkali cations of silica-supported Fe(III) sites for alkane oxidation

Abstract

Funding

Keywords

ASJC Scopus subject areas

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