Zirconia nanoparticles

Keywords dehydration, dehydrogenation, nanoparticles, zirconia, anion impurity, hydrogen, tight-binding theory, electronic structure. 

Sholklapper et al. [204] studied the structure and performance stability of a nanoparticle-infiltrated LSM in porous scandia-stabilized zirconia (SSZ) electrode at 650°C. The infiltrated LSM particles were 100 nm in diameter and some orientation alignment of the LSM nanoparticles within SSZ was observed after the cathodic polarization at 150 mAcnr2 for 500 h. However, there is no voltage degradation under the conditions studied. 

H. Althues, and S. Kaskel, Sulfated zirconia nanoparticles synthesized in reverse microemulsions preparation and catalytic properties, Langmuir 18, 7428—7435 (2002). 

The best known heterogeneous catalysts are oxide-supported Ru, Rh, and Ni, and Ru exhibits the highest selectivity. Marked support effects are observed and Ti02 is usually found to be the best support material. Pd on zirconia and Ni on zirconia are particularly effective catalysts when prepared using amorphous Pd-Zr, Ni-Zr, and Ni-containing multicomponent alloys by controlled oxidation-reduction treatment240-242 or generated under reaction conditions.243-245 Stabilized metal nanoparticles of uniform dispersion embedded into the oxide matrix are the... 

A. Hartridge, A. Bhattacharya, Preparation and analysis of zirconia doped ceria nanocrystal dispersions, J. Nanoparticle Res. 1 (2001) 75-80. 

Mesoporous silica containers can be used as inhibitor hosts with controlled release properties triggered at the beginning of the corrosion process in response to local pH changes. For instance, mesoporous silica nanoparticles covered with polyelectrolyte layers can be loaded with an inhibitor (2-(benzothiazol-2-ylsulfanyl)-succinic acid) prior to introduction into a hybrid zirconia-silica sol-gel film. This hierarchical design avoids spontaneous release of the inhibitor by the formation of a polyelectrolyte shell over the container s outermost surface. 

New developments in the quantum chemistry methodology, make it possible to obtain new data concerning the electronic structure of surface of zirconia nanoparticle and the dopants in it. 

On the basis of these models within the framework of computer modeling of processes in works [4-6] we estimated influence cation S and D impurity elements on energy of connection of hydrogen with zirconia nanoparticles. 

We used a cluster of 25 atoms (8 Zr atoms, 1 A atom, 15 0 atoms and 1 H atoms) for calculation of energy levels of the zirconia nanoparticle with hydroxyl group of bridge type (Fig. 1). The chemical formula of the cluster can be written down as Zr8AOi4 (OH), where (A = B, C, N, O, F, Ne). 

Figure 1. The structure of three-coordinated (bridge type) hydroxyl group on a surface (111) crystal zirconia nanoparticle.

Althues and Kaskel (2002) TEM, TG-MS Sulfated zirconia (synthesis of nanoparticles) Synthesis optimization by crystallization + + n.a. Butane isomerization... 

Nanosized ceria-zirconia materials with improved thermal stability can be prepared by using the surfactant-assisted method. Structural refinements confirm that the nanocrystals contain structural microstrain and cationic lattice defects. Zirconium addition to ceria supresses the crystal sintering and imporves the thermal stability but leads to structure distortion. Both catalytic tests and CO-chemisorption show that Pd supported ceria-zirconia nanoparticles are active for CO oxidation. 

S Atomistic simulation assisted synthesis and investigations The classical atomistic simulation techniques based on the pair potentials are suitable for the simulations of ceria nanoparticles even with a real sized model. Molecular d)mamics studies with several thousands of ions and up to hundreds of nanoseconds in a time scale have been carried out to interpret the diffusion, and crystal growth behaviors for pure and doped-ceria nanoparticles. Traditionally, the technique has been used to explore the oxygen ionic conductivity in ionic conductors such as ceria and zirconia (Maicaneanu et al., 2001 Sayle et al., 2006). 

The preparation of the required microporous ceramic layers is possible by the sol-gel route from stable colloidal dispersions with individual nanoparticles of less than 10 nm. Different types of ceramic nanofilters have been prepared from such aqueous or organic sols of the following oxides y-alumina, zirconia, ° hafnia," and titania. ... 

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