Microstructure and oxygen release properties of catalytic alumina-supported CeO2–ZrO2 powders

Ozawa, Masakuni; Matuda, Kazue; Suzuki, Suguru

doi:10.1016/s0925-8388(00)00605-8

Cited by 71 publications

(48 citation statements)

References 21 publications

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“…For example, it has been reported that the incorporation of Zr 4? to CeO 2 forms Ce x Zr 1-x O 2 solid solution, leading to the decrease of cell volume, lowering the activation energy for oxide-ion diffusion and increasing the OSC and thermal stability [11,12]. Similar phenomenon was also observed by Hf 4?…”

Section: Introductionmentioning

confidence: 60%

Effect of Mg Addition on the Physical and Catalytic Properties of Cu/CeO2 for NO + CO Reduction

Chen

Zhan

et al. 2009

Catal Lett

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Copper catalysts supported on magnesia promoted ceria are synthesized and used for NO reduction by CO. The supports and the subsequent Cu catalysts are prepared by citric acid sol-gel and impregnation methods, respectively. The results of N 2 -physisorption, XRD, EPR and TPR measurements indicate that the Mg addition promotes not only the dispersion of CuO, but also the formation of Cu-O-Ce solid solution. The highest amount of Cu-O-Ce solid solution is found in catalyst modified with 5 wt.% MgO . Based on the catalytic performance, two active sites for the reduction NO by CO are proposed: copper matrix and Cu-O-Ce solid solution. The former does not require the involvement of oxygen vacancy and is more active at low temperature range (T \ 200°C), while the latter shows higher NO conversion at temperature above 200°C, due to the easy regeneration of oxygen vacancy. Also, it is found that the NO conversion over copper matrix is suppressed, while that over Cu-O-Ce solid solution is stimulated in high CO concentration.

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Section: Introductionmentioning

confidence: 60%

Effect of Mg Addition on the Physical and Catalytic Properties of Cu/CeO2 for NO + CO Reduction

Chen

Zhan

et al. 2009

Catal Lett

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“…The potential oxygen storage capacities (OSC) of the supports were evaluated at temperatures ranging from 300 to 900°C, according to a procedure reported previously [36,37]. Changes in weight of the sample were monitored by thermogravimetry (TG-DSC analyzer, Q-600) under cyclic heat treatments in flowing nitrogen or dry air.…”

Section: Measurement Of Relative Oxygen Storage Capacities For As-prementioning

confidence: 99%

Catalytic Steam Reforming of Propane over Ni/LaAlO3 Catalysts: Influence of Preparation Methods and OSC on Activity and Stability

et al. 2011

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To develop an efficient catalyst for steam reforming of propane, Ni/LaAlO 3 catalysts were prepared by deposition precipitation, impregnation, and solvo-thermal methods, and characterized by XRD, BET, H 2 -TPR, elemental analyses, and TEM. Ni/Al 2 O 3 and Ni/CeO 2 catalysts were also synthesized by the solvo-thermal method for comparison. The Ni/LaAlO 3 catalysts exhibited better catalytic performance than both Ni/Al 2 O 3 and Ni/CeO 2 catalysts, and activities with Ni/LaAlO 3 were found to be dependent upon the preparation methods. In particular, the Ni/LaAlO 3 catalyst synthesized by the solvo-thermal method exhibited the highest activity presumably because tetrahydrofuran helps distribute generated Ni nanoparticles onto the catalyst surface in a uniform fashion. In addition, the solvo-thermally prepared Ni/LaAlO 3 catalyst was found to be highly stable, with its activity being maintained at least during 100 h. The observed high stability is attributed to the excellent oxygen storage capacity of LaAlO 3 , which was first determined by thermogravimetric methods as well as by soot oxidations in the presence of Al 2 O 3 , CeO 2 , and LaAlO 3 . Compared to the Ni/Al 2 O 3 and Ni/CeO 2 catalysts, Ni/LaAlO 3 exhibited suppressed carbon formation even at lower S/C ratios due to the superior oxygen transport ability of the LaAlO 3 support.

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“…The heat cycle consisted of heating the sample to 1073 K, cooling to 423 K, and again heating to 1073 K. All heating and cooling rates were in the steps of 5 K min -1 . The weight loss of the sample during the second stage of heat treatment was used to measure the oxygen release property [19].…”

Section: Evaluation Of Solid Solutionsmentioning

confidence: 99%

Design of Efficient CexM1−xO2−δ (M = Zr, Hf, Tb and Pr) Nanosized Model Solid Solutions for CO Oxidation

2010

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Nanosized Ce x M 1-x O 2-d (M = Zr, Hf, Tb and Pr) solid solutions were prepared by a modified coprecipitation method and thermally treated at different temperatures from 773 to 1073 K in order to ascertain the thermal behavior. The structural and textural properties of the synthesized samples were investigated by means of X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), BET surface area, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy (RS) techniques. The catalytic efficiency has been performed towards oxygen storage/release capacity (OSC) and CO oxidation activity. The characterization results indicated that the obtained solid solutions exhibit defective cubic fluorite structure. The solid solutions of ceria-hafnia, ceria-terbia and ceria-praseodymium exhibited good thermal stability up to 1073 K. A new Ce 0.6 Zr 0.4 O 2 phase along with Ce 0.75 Zr 0.25 O 2 was observed in the case of ceria-zirconia solid solution due to more Zr 4? incorporation in the ceria lattice at higher calcination temperatures. The reducibility of ceria has been increased upon doping with Zr 4? , Hf 4? , Tb 3?/4? and Pr 3?/4? cations. This enhancement is more in case of Hf 4? doped ceria. Among various solid solutions investigated, the ceria-hafnia combination exhibited better OSC and CO oxidation activity. The high efficiency of Ce-Hf solid solution was correlated with its superior bulk oxygen mobility and other physicochemical characteristics.

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Microstructure and oxygen release properties of catalytic alumina-supported CeO2–ZrO2 powders

Cited by 71 publications

References 21 publications

Effect of Mg Addition on the Physical and Catalytic Properties of Cu/CeO2 for NO + CO Reduction

Effect of Mg Addition on the Physical and Catalytic Properties of Cu/CeO2 for NO + CO Reduction

Catalytic Steam Reforming of Propane over Ni/LaAlO3 Catalysts: Influence of Preparation Methods and OSC on Activity and Stability

Design of Efficient CexM1−xO2−δ (M = Zr, Hf, Tb and Pr) Nanosized Model Solid Solutions for CO Oxidation

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