Nanostructures ceria

R. Valencuela, G. Bueno, A. Solbes, Nanostructured ceria-based catalysts for oxydehydrogenation of ethane with CO2, Topics Catal. 15 (2-4) (2001) 181-187. 

Related systems It should be noted that specific properties for applications could be enhanced by using solid solutions, doped materials, and composites, instead of pure ceria. For example, ceria-zirconia solid solution is a well known ceria based material for enhanced OSC and high ionic conductivity for solid state fuel cell components. It is also used in the three way catalysts for automobile waste gas cleaning, because of the improved thermal stability, surface area, and reducibility. The synthesis, structure, and properties of ceria-zirconia have been actively studied for a long time. Di Monte and Kaspar et al. presented feature articles on the nanostructured ceria—zirconia-mixed oxides. The studies on phase, structures, as well as the microstructures are discussed and reviewed (Di Monte et al., 2004). 

Aruna, S.T., Patil, K.C. Combustion synthesis and properties of nanostructured ceria-zirco-nia solid solutions. Nanostruct. Mater. 10, 955-964 (1998)... 

Kayama T, Yamzaki K, Shinjoh H (2010) Nanostructured ceria-sUver synthesized in a one-pot redox reaction catalyzes carbon oxidation. J Am Chem Soc 132 13154—13155... 

The water gas shift reaction (CO+HgO Hg+COg) is one of the critical processes for providing hydrogen for industrial applications. Ceria-noble metal composite catalysts have proved to be a competitive alternative for traditional catalysts in low-temperature water gas shift (LTS) reactions. Flytzani-Stephanopoulos and co-workers made a series of studies on nanostructured ceria-gold composite catalysts for The composite was made of ceria or La-doped ceria... 

Valechha et al synthesized porous nanostructured ceria by using chitosan as a biological template. The catalytic activity of various ceria-based samples for CO oxidation was evaluated using a fixed-bed quartz reactor at atmospheric pressure. The Tjofor a Pt/3 (1 3 of Ce and chitosan) catalyst was 94 °C and 100% CO conversion was achieved at 160 C at a space velocity of 60000 h f CO oxidadon over various samples prepared under different concentra-dons (SI to S7) is shown in Fig. 8.33. 

Valenzuela, R. X., Bueno, G., Solbes, A., Sapina, R, Martinez, E., and Cortes Corberan, V. Nanostructured ceria-based catalysts for oxydehydrogenation of ethane withCO. Top. Catal. 15,181-188 (2001). 

Deshpande, A. S. Pinna, N. Smarsly, B. Antonietti, M. Niederberger, M. 2005. Controlled assembly of preformed ceria nanocrystals into highly ordered 3D nanostructures. Small 1 313-316. 

In the past decade, controlled synthesis of ceria based nanomaterials, such as obtaining the pure phase, doping for desirable composition, controlling uniform size, shape, and nanostructure, tuning surfaces, fabricating composites, assemblies and mesostructures, have been the targets of active research since ceria-based materials exhibits unique properties when their sizes are reduced to nanometer scale. 

Since ceria exhibits a cubic fluorite crystal structure, the noncubic nanostructures, such as NRs, NWs, and nanoplates, are fabricated under experimental conditions that are suitable to break dovm the symmetry. One general way is to exploit an appropriate intermediate, such as Ce(OH)3 or Ce(OH)C03. The rare earth hydroxide crystalline NRs/NWs/ NTs are obtained in basic solutions imder hydrothermal treatment, which is discussed in Section 2.3. If certain oxidant is present in the hydrothermal treatment, the ceria NCs could be obtained in a one pot manner. In this way, rod-like, wire-like, or tube-like nanoceria could be synthesized. If the hydrothermal treatment is carried out under oxygen free... 

Zhou et al. reported the synthesis of flower-like ceria NPs by thermal decomposition of (NH4)2Ce(N03)g in OA/OM solvents at 230-300 °C. The small ceria nanoparticles form, assemble, and fuse mainly via (111) faces by oriented attachment. Monitoring by in situ electrical resistance measurements shows that the conductive species are diminished when the flower-like nanostructures form (Zhou et al., 2008a Figure 6). Ceria nanoflowers and nanocubes are also obtained in octadecylamine, with higher temperature for nanoflower and lower temperature for nanocubes. The obtained colloidal nanoparticles can be self-assembled into nanospheres assisted by SDS surfactants (Wang et al., 2008a). 

Guillou et al., 1997 Kleinlogel and Gauckler, 2000 Purohit et al., 2001 Trovarelli et al., 1997). The method by annealing of cerium hydroxides or cerium hydroxyl carbonates with special nanostructures is used to obtain ceria nanostructure, which has been discussed above. 

Mesoporous ceria—zirconia nanostructures could be obtained through evaporation induced self assembly process (Yuan et al. 2007 Figure 8). Such ordered nanostructures may show promising applications in catalysis and sensors with special selectivities. 

Sayle et al. (2008) also developed (Figure 9) a route exploiting the classical atomistic simulation to make combined studies of theoretical and experimental works. A typical selected system is ceria. Since the pair potential model based on electrostatic interaction and Buckingham short range presentations are often adequate to describe the fluorite structure of ceria, Sayle et al. explored the application of such models in nano-sized particles. A series of works have been reported on the assembly behaviors of nano-building blocks into complex nanostructures, including the ceria nanoparticles self assembly in ice mold (Karakoti... 

Chemical and Nanostructural Aspects of the Preparation and Characterisation of Ceria and Ceria-Based Mixed Oxide Supported Metai Cataiysts ... 

Tlie CVD method is usually used to produce a thin film material which is formed on a heated substrate. However, nanostructured particles of ceria and ceria-yttria have been synthesized by some arrangements of the apparatus. Figure 3.8 shows the schematic CVD reactors for synthesizing ceria-based nanopanicles.Two types of rector has been presented. The nanoparticles are collected either on a cooled quartz susceptor (A) that is in a furnace, or in a cold wall container outside the furnace (B), The precursor cerium chloride set on the container is evaporated and... 

CHEMICAL AND NANOSTRUCTURAL ASPECTS OF THE PREPARATION AND CHARACTERISATION OF CERIA AND CERIA BASED MIXED OXIDE-SUPPORTED... 

Chemical and nanostructural charaterization of metal/ceria systems... 

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