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Insight in kinetics from pre-edge features using time resolved in situ XAS

(2018) AICHE JOURNAL. 64(4). p.1339-1349
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Abstract
The kinetics of reduction of a 10 wt %Fe2O3-MgAl2O4spinel were investigated using XRD and time resolved Fe-KQXANES. The Rietveld refinement of the XRD pattern showed the replacement of Al with Fe in the spinel structure andthe formation of MgFeAlOx. The XANES pre-edge feature was employed to study the reduction kinetics during H2-TPR(Temperature Programmed Reduction) up to 7308C. About 55% of the Fe31in MgFeAlOxwas reduced to Fe21. Ashrinking core model, which takes into account both solid-state diffusion via an oxygen diffusion coef ficient, and gas-solid reaction through a reaction rate coefficient, was applied. The activation energy for chemical reaction showed alinear dependence on the conversion, increasing from 104 to 126 kJ/mol over the course of material reduction. The good accordance between the shrinking core model description and the experimental data indicates that XANES pre-edge features can be used to correlate changes in material structure and reaction kinetics.
Keywords
CHEMICAL-LOOPING COMBUSTION, FE K-EDGE, IRON OXIDATION-STATE, SHRINKING CORE MODEL, X-RAY-DIFFRACTION, ENERGY-STORAGE, MULTIPLET ANALYSIS, CO2 UTILIZATION, OXYGEN CARRIER, CONVERSION

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Chicago
Dharanipragada, Naga Venkata Ranga Aditya, Vladimir Galvita, Hilde Poelman, Lukas Buelens, Alessandro Longo, and Guy Marin. 2018. “Insight in Kinetics from Pre-edge Features Using Time Resolved in Situ XAS.” Aiche Journal 64 (4): 1339–1349.
APA
Dharanipragada, N. V. R. A., Galvita, V., Poelman, H., Buelens, L., Longo, A., & Marin, G. (2018). Insight in kinetics from pre-edge features using time resolved in situ XAS. AICHE JOURNAL, 64(4), 1339–1349.
Vancouver
1.
Dharanipragada NVRA, Galvita V, Poelman H, Buelens L, Longo A, Marin G. Insight in kinetics from pre-edge features using time resolved in situ XAS. AICHE JOURNAL. 2018;64(4):1339–49.
MLA
Dharanipragada, Naga Venkata Ranga Aditya et al. “Insight in Kinetics from Pre-edge Features Using Time Resolved in Situ XAS.” AICHE JOURNAL 64.4 (2018): 1339–1349. Print.
@article{8556837,
  abstract     = {The kinetics of reduction of a 10 wt \%Fe2O3-MgAl2O4spinel were investigated using XRD and time resolved Fe-KQXANES. The Rietveld re\unmatched{fb01}nement of the XRD pattern showed the replacement of Al with Fe in the spinel structure andthe formation of MgFeAlOx. The XANES pre-edge feature was employed to study the reduction kinetics during H2-TPR(Temperature Programmed Reduction) up to 7308C. About 55\% of the Fe31in MgFeAlOxwas reduced to Fe21. Ashrinking core model, which takes into account both solid-state diffusion via an oxygen diffusion coef \unmatched{fb01}cient, and gas-solid reaction through a reaction rate coef\unmatched{fb01}cient, was applied. The activation energy for chemical reaction showed alinear dependence on the conversion, increasing from 104 to 126 kJ/mol over the course of material reduction. The good accordance between the shrinking core model description and the experimental data indicates that XANES pre-edge features can be used to correlate changes in material structure and reaction kinetics.},
  author       = {Dharanipragada, Naga Venkata Ranga Aditya and Galvita, Vladimir and Poelman, Hilde and Buelens, Lukas and Longo, Alessandro and Marin, Guy},
  issn         = {0001-1541 },
  journal      = {AICHE JOURNAL},
  language     = {eng},
  number       = {4},
  pages        = {1339--1349},
  title        = {Insight in kinetics from pre-edge features using time resolved in situ XAS},
  url          = {http://dx.doi.org/10.1002/aic.16017},
  volume       = {64},
  year         = {2018},
}

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