Authors: Ke Hui Qiu, Yan Rong Wang, Pei Cong Zhang, Wei Zhang
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Authors: N. Sabari Arul, D. Mangalaraj, N. Ponpandian, Pao Chi Chen, Junsin Yi
Abstract: Cerium-iron oxide composite nanorods were synthesized by a surfactant free precipitation method. The synthesized products were characterized by XRD, FESEM, BET and TEM. Increase in the mole concentration causes the morphology of the cerium oxide to change from nanorods into nanocubes. X-ray diffraction pattern shows a diffraction peak at 28.5° corresponding to (111) reflection plane normal to c axis of a cubic fluorite structure of CeO2 and also hexagonal phase of Fe2O3 and orthorhombic phase of FeO (OH). EDAX analysis on individual nanorod conform the presences of Iron, which supports the XRD spectra. From transmission electron microscopy (TEM), the length and width of the nanorods were estimated in the range of ~100-350 nm and ~20-40 nm respectively. The Brunauer Emmett Teller (BET) analysis showed the increase in surface area for the obtained nanorods with respect to the increase in Fe concentration which in turn enhanced the formation and growth of nanorods.
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Abstract: The surface and structural properties, thermal stability and oxygen storage capability are inverstigated in ceria-zirconia-alumina oxide with deposition coprecipitation method using the Pseudoboehmite precursor. X-ray diffraction (XRD), Brunauer-Emmet Teller method (BET), Transmission electron microscopy (TEM) and oxygen pulsing technique are used to character the prepared materials. The prepared ceria-zirconia-alumina oxides are highly dispersed composite solid solution. After calcination at 650 °C and 1000 °C respectively, these compounds can still keep the structural and textural stability and hold excellent oxygen storage capability.
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Authors: Jing Xu, Qing Hua Chen, Xin Ping Liu, Bao Quan Huang, Qing Rong Qian
Abstract: A nanoscale ceria-doped calcia solid solution has been synthesized by controled self-combustion method. The difference in crystal structure of samples prepared from different fuels were identified by XRD. The change of the crystal structure of the ceria-doped calcia sintering at different temperature was also investigated. SEM indicates that a nanoscale and uniform particle with diameter less than 100 nm was achieved by this method.
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Authors: Dae Han Lee, Dong Sik Bae
Abstract: Ba doped CeO2 nanopowders were prepared under mild temperature and pressure conditions by precipitation from metal nitrates with aqueous ammonium hydroxide. Spherical Ba doped CeO2 nanopowders were obtained with reaction at the temperature range of 210°C to 230°C for 6 h. The average size of the synthesized Ba doped CeO2 powders were below 10 nm and its distribution was narrow. The XRD pattern showed that the synthesized Ba doped CeO2 powders were crystalline with cubic phase of CeO2. This study has shown that the synthesis of Ba doped CeO2 nanopowders is possible under mild temperature and pressure conditions in ethylene gylcol solution. The effects of synthesis parameters, such as the solvent ratio of starting solution, pH of starting solution, reaction temperature and time, are discussed.
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