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Controlling the stability of a Fe-Ni reforming catalyst : structural organization of the active components

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Abstract
Fe-Ni catalysts present high activity in dry reforming of methane, with high carbon resistance, but suffer from deactivation via sintering and Fe segregation. Enhanced control of the stability and activity of Fe-Ni/MgAl2O4 was achieved by means of Pd addition. The evolution of the catalyst structure during H-2 Temperature Programmed Reduction (TPR) and CO2 Temperature Programmed Oxidation (TPO) was investigated using time-resolved in situ X-ray diffraction (XRD). During reduction of Fe-Ni-Pd supported on MgAl2O4, a core shell alloy forms at the surface, where Fe-Ni is in the core and Fe-Ni-Pd in the shell. A 0.2 wt% Pd loading or Ni:Pd molar ratio as high as 75:1 showed the best performance in terms of both activity and stability of the catalyst at 1023 K and total pressure of 101.3 kPa. Experimental results and DFT calculations showed that Pd addition to bimetallic Fe-Ni reduces the tendency of Fe to segregate to the surface of the alloy particles under methane dry reforming (DRM) conditions, due to the formation of a thin Fe-Ni-Pd surface layer. The latter acts as a barrier for Fe segregation from the core. Segregation of Fe from the trimetallic shell still occurs, but to a lesser extent as the Fe concentration is lower. This Ni:Pd molar ratio is capable of controlling the carbon formation and hence ensure high catalyst activity of 24.8 mmol s(-1) g(metals)(-1) after 21 h time-on-stream. (C) 2017 Elsevier B.V. All rights reserved.
Keywords
INITIO MOLECULAR-DYNAMICS, TOTAL-ENERGY CALCULATIONS, TAR, MODEL-COMPOUND, WAVE BASIS-SET, CARBON-DIOXIDE, BIOMASS TAR, SYNTHESIS, GAS, BIMETALLIC CATALYSTS, METHANE CONVERSION, PARTIAL OXIDATION, Synthesis gas, Catalyst stability, In situ XRD, Fe-Ni alloy, Methane, reforming

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Chicago
Theofanidis, Stavros-Alexandros, Vladimir Galvita, Maarten Sabbe, Hilde Poelman, Christophe Detavernier, and Guy Marin. 2017. “Controlling the Stability of a Fe-Ni Reforming Catalyst : Structural Organization of the Active Components.” Applied Catalysis B-environmental 209: 405–416.
APA
Theofanidis, S.-A., Galvita, V., Sabbe, M., Poelman, H., Detavernier, C., & Marin, G. (2017). Controlling the stability of a Fe-Ni reforming catalyst : structural organization of the active components. APPLIED CATALYSIS B-ENVIRONMENTAL, 209, 405–416.
Vancouver
1.
Theofanidis S-A, Galvita V, Sabbe M, Poelman H, Detavernier C, Marin G. Controlling the stability of a Fe-Ni reforming catalyst : structural organization of the active components. APPLIED CATALYSIS B-ENVIRONMENTAL. Amsterdam: Elsevier Science Bv; 2017;209:405–16.
MLA
Theofanidis, Stavros-Alexandros, Vladimir Galvita, Maarten Sabbe, et al. “Controlling the Stability of a Fe-Ni Reforming Catalyst : Structural Organization of the Active Components.” APPLIED CATALYSIS B-ENVIRONMENTAL 209 (2017): 405–416. Print.
@article{8531365,
  abstract     = {Fe-Ni catalysts present high activity in dry reforming of methane, with high carbon resistance, but suffer from deactivation via sintering and Fe segregation. Enhanced control of the stability and activity of Fe-Ni/MgAl2O4 was achieved by means of Pd addition. The evolution of the catalyst structure during H-2 Temperature Programmed Reduction (TPR) and CO2 Temperature Programmed Oxidation (TPO) was investigated using time-resolved in situ X-ray diffraction (XRD). During reduction of Fe-Ni-Pd supported on MgAl2O4, a core shell alloy forms at the surface, where Fe-Ni is in the core and Fe-Ni-Pd in the shell. A 0.2 wt\% Pd loading or Ni:Pd molar ratio as high as 75:1 showed the best performance in terms of both activity and stability of the catalyst at 1023 K and total pressure of 101.3 kPa. Experimental results and DFT calculations showed that Pd addition to bimetallic Fe-Ni reduces the tendency of Fe to segregate to the surface of the alloy particles under methane dry reforming (DRM) conditions, due to the formation of a thin Fe-Ni-Pd surface layer. The latter acts as a barrier for Fe segregation from the core. Segregation of Fe from the trimetallic shell still occurs, but to a lesser extent as the Fe concentration is lower. This Ni:Pd molar ratio is capable of controlling the carbon formation and hence ensure high catalyst activity of 24.8 mmol s(-1) g(metals)(-1) after 21 h time-on-stream. (C) 2017 Elsevier B.V. All rights reserved.},
  author       = {Theofanidis, Stavros-Alexandros and Galvita, Vladimir and Sabbe, Maarten and Poelman, Hilde and Detavernier, Christophe and Marin, Guy},
  issn         = {0926-3373},
  journal      = {APPLIED CATALYSIS B-ENVIRONMENTAL},
  keyword      = {INITIO MOLECULAR-DYNAMICS,TOTAL-ENERGY CALCULATIONS,TAR,MODEL-COMPOUND,WAVE BASIS-SET,CARBON-DIOXIDE,BIOMASS TAR,SYNTHESIS,GAS,BIMETALLIC CATALYSTS,METHANE CONVERSION,PARTIAL OXIDATION,Synthesis gas,Catalyst stability,In situ XRD,Fe-Ni alloy,Methane,reforming},
  language     = {eng},
  pages        = {405--416},
  publisher    = {Elsevier Science Bv},
  title        = {Controlling the stability of a Fe-Ni reforming catalyst : structural organization of the active components},
  url          = {http://dx.doi.org/10.1016/j.apcatb.2017.03.025},
  volume       = {209},
  year         = {2017},
}

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