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Meyer, Michael; Rüffler, Regina

doi:10.1023/a:1021228119983

Cited by 8 publications

(3 citation statements)

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“…XRD of the initial olivine (Figure ) shows the same main lines as those in the theoretical diffractogram of (Mg 0.9 Fe 0.1 ) 2 SiO 4 , which are close to those of the Mg 2 SiO 4 forsterite visualized by its 100-intensity line at 28.2° 2θ, and a spinel cubic phase, which could be either γ-Fe 2 O 3 , Fe 3 O 4 , or MgFe 2 O 4 magnesioferrite (and/or members of solid solutions such as MgFe 2 O 4 −Fe 3 O 4 and MgFe 2 O 4 −γ-Fe 2 O 3 ) . XRD does not permit us to distinguish between those three phases, which have nearly the same diffraction patterns .…”

Section: Resultssupporting

confidence: 63%

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Oxidation Reduction Behavior of Iron-Bearing Olivines (Fe_xMg_1-_x)₂SiO₄ Used as Catalysts for Biomass Gasification

et al. 2006

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Natural iron-bearing olivines (Fe x Mg 1-x ) 2 SiO 4 have been recognized as one of the most promising tar-cracking catalytic materials for fluidized bed biomass gasification to produce syngas (H 2 + CO). Iron present in the olivine significantly influences its catalytic activity. However, the Fe 0 -active phase cannot be obtained by the reduction of olivine under the catalyst working conditions. A better understanding of olivine's behavior in oxidizing-reducing conditions is crucial for control of its catalytic properties. In this paper, we have demonstrated how the oxidation of iron-bearing olivines leads to the formation of reducible iron oxides dispersed in the iron-depleted olivine matrix. The choice of oxidation-reduction conditions permits us to control the amount of iron extracted from the olivine structure. The mechanism of the oxidation-reduction behavior of a natural olivine has been studied by 57 Fe Mo ¨ssbauer spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and temperature-programmed reduction (TPR).

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Section: Resultssupporting

confidence: 63%

“…This apparent ferrous doublet is in fact a superposition of two doublets caused by Fe 2+ at the M1 and M2 sites of the olivine lattice. These doublets strongly overlap and are therefore not resolvable; they had to be fitted by one hyperfine pattern …”

Section: Resultsmentioning

confidence: 99%

Oxidation Reduction Behavior of Iron-Bearing Olivines (Fe_xMg_1-_x)₂SiO₄ Used as Catalysts for Biomass Gasification

et al. 2006

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“…The parameters of the three subspectra for Ni/olivine calcined at 1100 and 1400 °C are given in Table . The quadrupole doublet present in the Mössbauer spectra with an isomer shift of ∼1.12 mm s -1 and quadrupole splitting of ∼3.06 mm s -1 is due to Fe 2+ ions in the olivine structure , They can be attributed to the iron in the form of α-Fe 2 O 3 and spinel phase (MgFe 2 O 4 ).…”

Section: Resultsmentioning

confidence: 98%

Characterization of Ni−Fe/MgO/Olivine Catalyst for Fluidized Bed Steam Gasification of Biomass

et al. 2006

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Tar removal catalyst development is the main hurdle to improving the process of steam biomass gasification in a fluidized bed. A Ni/olivine catalyst has been previously developed to enhance the catalytic properties of calcined natural olivine and showed excellent performance and stability during biomass steam gasification in the fast internally circulating fluidized bed (FICFB) gasifier. However, the origin of its active phase was not well-understood. The present work explains the mechanism of formation and the nature of the active phase of the Ni/olivine catalyst, characterized before testing, after calcination, and after reduction by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature-programmed reduction (TPR), and 57Fe Mössbauer spectroscopy. Two phenomena contribute to the formation of this active system: the formation of a NiO−MgO solid solution on the olivine surface during calcination and Ni−Fe alloys during the reduction, both of which are known to have beneficial effects on increasing carbon deposition resistance. The catalyst, resulting from subsequent calcination and reduction of the precursor after the impregnation of natural olivine with nickel nitrate, can be described as a Ni−Fe/MgO/olivine system. Its catalytic performances are confirmed in the steam reforming of methane and toluene as a tar model compound.

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Nickel supported on iron-bearing olivine for CO2 methanation

Wang

Jiang

et al. 2016

International Journal of Hydrogen Energy

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Untitled

Cited by 8 publications

References 9 publications

Oxidation Reduction Behavior of Iron-Bearing Olivines (Fe_xMg_1-_x)₂SiO₄ Used as Catalysts for Biomass Gasification

Oxidation Reduction Behavior of Iron-Bearing Olivines (Fe_xMg_1-_x)₂SiO₄ Used as Catalysts for Biomass Gasification

Characterization of Ni−Fe/MgO/Olivine Catalyst for Fluidized Bed Steam Gasification of Biomass

Nickel supported on iron-bearing olivine for CO2 methanation

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Untitled

Cited by 8 publications

References 9 publications

Oxidation Reduction Behavior of Iron-Bearing Olivines (FexMg1-x)2SiO4 Used as Catalysts for Biomass Gasification

Oxidation Reduction Behavior of Iron-Bearing Olivines (FexMg1-x)2SiO4 Used as Catalysts for Biomass Gasification

Characterization of Ni−Fe/MgO/Olivine Catalyst for Fluidized Bed Steam Gasification of Biomass

Nickel supported on iron-bearing olivine for CO2 methanation

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Oxidation Reduction Behavior of Iron-Bearing Olivines (Fe_xMg_1-_x)₂SiO₄ Used as Catalysts for Biomass Gasification

Oxidation Reduction Behavior of Iron-Bearing Olivines (Fe_xMg_1-_x)₂SiO₄ Used as Catalysts for Biomass Gasification