The Reduction of Mg–Fe–O and Mg–Fe–Al–O Complex Oxides Studied by Temperature-Programmed Reduction Combined with in Situ Mössbauer Spectroscopy

Ge, Xinlei; Li, Mingshi; Shen, Jianyi

doi:10.1006/jssc.2001.9264

Cited by 56 publications

(27 citation statements)

References 28 publications

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“…As confirmed by TPR profile [ Fig. 2 (a)], Fe 0 is here obtained via the reduction of αFe 2 O 3 → Fe 3 O 4 , mainly occurring at low temperature, followed by the steps Fe 3 O 4 → FeO→ Fe, above 500°C [4].…”

Section: Catalystssupporting

confidence: 55%

Synthesis and analysis of multi-walled carbon nanotubes/oxides hybrid materials for polymer composite applications

Piperopoulos¹,

Santangelo²,

Lanza³

et al. 2011

Diamond and Related Materials

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Section: Catalystssupporting

confidence: 55%

Synthesis and analysis of multi-walled carbon nanotubes/oxides hybrid materials for polymer composite applications

Piperopoulos¹,

Santangelo²,

Lanza³

et al. 2011

Diamond and Related Materials

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“…The obtained signals are shown in Figure 3. All profiles exhibit two distinct peaks that shift towards highert emperatures as af unctiono fb.T hus, the reduction of the spinels is ap rocess involving two consecutive steps as reported by Ge et al [14] The authors performed an investigation over MgFe 2 O 4 and MgFeAlO 4 using ac ombination of H 2 -TPR and in situ Mçssbauer spectroscopy,a llowing them to propose the followingr eactions:…”

Section: Reducibility Of Pure and Substituted Magnesioferritesmentioning

confidence: 98%

“…Iron is knownt of orm as olid solution with magnesium, [14] whichi s represented by Mg 1-x Fe II x Oi nr eactions (2a) and (2b). Thereupon,t he formation of a-Fe from Fe 2 + is retarded due to the presenceo fM g 2 + as ac omplete separation of both speciesi s required by diffusion events.…”

Section: Reducibility Of Pure and Substituted Magnesioferritesmentioning

confidence: 99%

Ammonia Decomposition and Synthesis over Multinary Magnesioferrites: Promotional Effect of Ga on Fe Catalysts for the Decomposition Reaction

et al. 2017

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Magnesioferrite (MgFe2O4)‐derived Mesoporous spinels of the type MgFeM3+O4 with M3+=Fe, Al, and Ga obtained upon calcination of hydrotalcite‐like compounds were investigated in the ammonia decomposition reaction at 1 bar and the synthesis of ammonia at 90 bar. The corresponding precursors were synthesized by co‐precipitation at 50 °C and constant pH of 10.5. N2 physisorption, PXRD, HR‐TEM, H2‐TPR, and NH3‐TPD were applied in order to obtain information about the textural, (micro‐)structural, solid‐state kinetics in reducing atmosphere, and adsorption properties of the samples. While phase‐pure layered double hydroxides (LDHs) were obtained for Al and Ga, magnesioferrite as the desired oxide phase and a low fraction of magnetite were formed besides the targeted precursor phase during co‐precipitation in the presence of Fe2+ and Fe3+ species. Reduction of the binary and ternary magnesioferrites occurs via two consecutive reactions. Only the second stage is shifted towards higher temperatures after incorporation of Al and Ga. The latter element boosts the catalytic decomposition of ammonia, yielding a 2‐fold and 5‐fold higher conversion at 500 °C compared to the samples containing Fe3+ and Al3+ species, respectively. In situ XRD measurements showed that this unprecedented promotional effect is related to the generation of (Fe, Ga)Fe3N. This phase, however, is detrimental for the synthesis of ammonia at elevated pressures in which the binary system outperforms the ternary spinels, yielding 30 % of the activity obtained with a highly promoted Fe‐based industrial catalyst.

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“…For instance there are two strong peaks at about 450 and 750°C. They are corresponding to the reduction process of Fe 3+ → Fe 2+ (low temperature peak) and Fe 2+ → Fe (high temperature peak) [4,6,16]. As a whole, higher CeO 2 content hinders the reducibility of Fe 3+ (Fe 2 O 3 ) to Fe 2+ (Fe 3 O 4 ) [10].…”

Section: H 2 -Tpr Testsmentioning

confidence: 98%

“…Recent studies have shown that transition metal promoters, such as MgO and CeO 2 , could improve the catalytic activities of Fe 2 O 3 -K 2 O based catalysts [5][6][7][8][9][10][11][12]. CeO 2 cannot only accelerate styrene formation, but also prevent potassium loss and prolong the service life of catalysts [8,10].…”

Section: Introductionmentioning

confidence: 99%

Optimum ratio of K2O to CeO2 in a wet-chemical method prepared catalysts for ethylbenzene dehydrogenation

Cui

Zhang

et al. 2016

Catalysis Communications

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The Reduction of Mg–Fe–O and Mg–Fe–Al–O Complex Oxides Studied by Temperature-Programmed Reduction Combined with in Situ Mössbauer Spectroscopy

Cited by 56 publications

References 28 publications

Synthesis and analysis of multi-walled carbon nanotubes/oxides hybrid materials for polymer composite applications

Synthesis and analysis of multi-walled carbon nanotubes/oxides hybrid materials for polymer composite applications

Ammonia Decomposition and Synthesis over Multinary Magnesioferrites: Promotional Effect of Ga on Fe Catalysts for the Decomposition Reaction

Optimum ratio of K2O to CeO2 in a wet-chemical method prepared catalysts for ethylbenzene dehydrogenation

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