Characteristics in oxygen storage capacity of ceria–zirconia mixed oxides prepared by continuous hydrothermal synthesis in supercritical water

Kim, Jeong‐Rang; Myeong, Wan-Jae; Ihm, Son Ki

doi:10.1016/j.apcatb.2006.08.015

Cited by 107 publications

(49 citation statements)

References 8 publications

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“…Zhang et al [27] reported the formation of nanocrystalline CeO 2 -ZrO 2 solid solutions by thermal decomposition of cerium and zirconium acetylacetonates in oleylamine; however, the reducibility of their materials was not reported. Hydrothermal treatment of coprecipitated gels was reported to increase the thermal stability of the CeO 2 -ZrO 2 solid solutions [28,29] In this work, CeO 2 -ZrO 2 solid solutions were prepared by the glycothermal method with a wide composition range, and their OSC and physical properties were investigated in comparison with the CeO 2 -ZrO 2 solid solutions obtained by a conventional co-precipitation method.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of CeO2–ZrO2 solid solution by glycothermal method and its oxygen release capacity

Hosokawa

Imamura

Iwamoto

et al. 2011

Journal of the European Ceramic Society

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The glycothermal (GT) reaction of Ce acetate and Zr alkoxide directly yielded CeO2-ZrO2 solid solutions in a region of low Ce content ≤40 mol%. Of the CeO2-ZrO2 solid solutions obtained by the GT method and subsequent calcination at 500 or 800 ºC, the sample with 20 mol% Ce content had the largest BET surface area. This sample exhibited the highest Ce-based oxygen release capacity in the whole Ce/Zr composition range.The oxygen release capacities of CeO 2 -ZrO 2 solid solutions synthesized by the GT method were much larger than those of the samples prepared by a coprecipitation (CP) method. The Rietvelt analysis and the repetitive reduction-oxidation experiment indicated that the CeO 2 -ZrO 2 solid solution synthesized by the GT method has a homogeneous structure as compared with that prepared by the CP method.2

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Section: Introductionmentioning

confidence: 99%

Synthesis of CeO2–ZrO2 solid solution by glycothermal method and its oxygen release capacity

Hosokawa

Imamura

Iwamoto

et al. 2011

Journal of the European Ceramic Society

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“…For fresh CZPA-P, the presence of two reduction peaks at 619 and 782°C indicates that there are at least two types of Ce 4+ located in different chemical environments. The reduction peak at 619°C could be assigned to the reduction of surface Ce 4+ , whereas the peak at 782°C could be assigned to the reduction of bulk Ce 4+ (He et al, 2003;Kim et al, 2007;Kim et al, 2009;Thammachart et al, 2001). The temperature of bulk reduction of fresh CZPA-P is lower than that of pure CeO 2 (Boaro et al, 2003) due to the increased mobility of bulk oxygen in fresh CZPA-P. After thermal aging, the reduction peaks in the TPR experiment with CZPA-S sample shifts slightly towards lower temperature.…”

Section: H 2 -Tprmentioning

confidence: 99%

Preparation and properties of nanophase (Ce, Zr, Pr)O2-doped alumina coating on cordierite ceramic honeycomb for three-way catalysts

Tian

2012

Braz. J. Chem. Eng.

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-Nanophase (Ce, Zr, Pr)O 2 -doped alumina coatings were prepared by impregnating the cordierite ceramic honeycomb in the sol or in the slurry of already calcined powder, respectively. The effects of preparation methods on the crystal phase, texture, oxygen storage capacity (OSC), reducibility, surface morphology and thermal stability of coatings were investigated by X-ray diffraction (XRD), the Brunauer Emmet Teller (BET) method, the oxygen pulsing technique, H 2 -temperature-programmed reduction (H 2 -TPR) and scanning electron microscopy (SEM). These nanophase (Ce, Zr, Pr)O 2 -doped alumina coatings were used as supports to prepare Pd-only three-way catalysts, and evaluated with respect to catalytic activities. The results indicate that the nanophase (Ce, Zr, Pr)O 2 -doped alumina coatings prepared by the two methods have high thermal stability. However, the coating derived from the sol shows better crystalline structure, texture, reducibility and oxygen storage capacity than the coating derived from the slurry. SEM observation shows that the morphology of the coating derived from the sol is uniform and smooth. The Pd-only catalyst derived from the sol exhibits high three-way catalytic activity at low temperature and thermal stability, suggesting a great potential for applications.

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“…The introduction of Zr 4+ ions into the CeO 2 lattice, for example, produces higher oxygen defects in the structure in quantity due to the formation of distortions in the fluorite-type structure of CeO 2 . These distortions are associated with the difference in the ionic radius of Ce 4+ and Zr +4 [11,12]. The modification of the lattice with secondary ions such as Cu 2+ with different oxidation states than Ce 4+ leads to the formation of additional structural defects associated with the neutralization of the total charge in the mixed metal oxide system [7].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of CeO2-based core/shell nanoparticles with high oxygen storage capacity

2017

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Ceria plays a key role in various applications including sensing and catalysis owing to its high oxygen storage capacity (OSC). The aim of this work is to prepare novel MO x /CeO 2 (M: Zr, Ti, Cu) metal oxide systems with core/shell structures using a facile two-step chemical precipitation method. The synthesized nanoparticles were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and N 2 adsorption methods. The OSC property of the samples was evaluated using TGA analysis conducted at 600°C under reductive (5% H 2 /Ar) and oxidative (synthetic air) environments. The OSCs of the samples were found to be 130, 253, and 2098 µmol-O 2 /g for ZrO 2 /CeO 2 , TiO 2 /CeO 2 , and CuO/ CeO 2 , respectively. Effects of heat treatment on the physical and redox properties of the samples were also evaluated. In this regard, the samples were exposed to 500°C for 5 h under ambient environment. It was observed that the heat treatment induced the formation of mixed metal oxide alloys and the BET surface area of the samples diminished significantly. The OSC of the samples, however, did not experience any significant chance, which was attributed to the compensation of the loss in the surface area by the alloy formation after the heat treatment.

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Characteristics in oxygen storage capacity of ceria–zirconia mixed oxides prepared by continuous hydrothermal synthesis in supercritical water

Cited by 107 publications

References 8 publications

Synthesis of CeO2–ZrO2 solid solution by glycothermal method and its oxygen release capacity

Synthesis of CeO2–ZrO2 solid solution by glycothermal method and its oxygen release capacity

Preparation and properties of nanophase (Ce, Zr, Pr)O2-doped alumina coating on cordierite ceramic honeycomb for three-way catalysts

Synthesis of CeO2-based core/shell nanoparticles with high oxygen storage capacity

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