Zirconia synthesis

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

The preparation of sulphated zirconia designed for catalyst supports was studied by Boutonnet et al. . Zirconia prepared in microemulsion showed a pure tetragonal structure compared with zirconia prepared by an impregnation -precipitation procedure which also contained monoclinic phase. Platinum-promoted sulphated zirconia catalysts were prepared both in anionic and non-ionic microemulsions. Furthermore, the catalytic activity and selectivity for the isomerization of hexanes were tested. The catalysts produced by the microemulsion method showed a higher selectivity towards isomers but a lower activity when compared to catalysts prepared by impregnation technique. More recently, a study of zirconia synthesis from micro and macroemulsion systems has been conducted . Spherical ZrOa particles ranging from tens of nanometers to a few micrometers were produced. 

Active heterogeneous catalysts have been obtained. Examples include titania-, vanadia-, silica-, and ceria-based catalysts. A survey of catalytic materials prepared in flames can be found in [20]. Recent advances include nanocrystalline Ti02 [24], one-step synthesis of noble metal Ti02 [25], Ru-doped cobalt-zirconia [26], vanadia-titania [27], Rh-Al203 for chemoselective hydrogenations [28], and alumina-supported noble metal particles via high-throughput experimentation [29]. 

Hu, Y. and Carr, P. W., Synthesis and characterization of new zirconia-based polymeric cation-exchange stationary phases for high-performance liquid chromatography, Anal. Chem., 70, 1934, 1996. 

Querino, do Carmo Rangel, and coworkers—improvement in catalytic activity by doping Pt/zirconia with Ce. Querino et al.469 reported that doping of a fraction of approximately 0.1 Ce to Pt/Zr02 led to enhanced activity for the high temperature shift reaction. The catalyst was prepared using a sol-gel synthesis... 

Ordered mesoporous materials of compositions other than silica or silica-alumina are also accessible. Employing the micelle templating route, several oxidic mesostructures have been made. Unfortunately, the pores of many such materials collapse upon template removal by calcination. The oxides in the pore walls are often not very well condensed or suffer from reciystallization of the oxides. In some cases, even changes of the oxidation state of the metals may play a role. Stabilization of the pore walls in post-synthesis results in a material that is rather stable toward calcination. By post-synthetic treatment with phosphoric acid, stable alumina, titania, and zirconia mesophases were obtained (see [27] and references therein). The phosphoric acid results in further condensation of the pore walls and the materials can be calcined with preservation of the pore system. Not only mesoporous oxidic materials but also phosphates, sulfides, and selenides can be obtained by surfactant templating. These materials have pore systems similar to OMS materials. 

D. Farcasiu and J. Q. Li, Preparation of sulfated zirconia catalysts with improved control of sulfur content, 111 effect of conditions of catalyst synthesis on physical properties and catalytic activity,... 

M. S. Wong, H. C. Huang, and J. Y. Ying, Supramolecular-templated synthesis of nanoporous zirconia-silica catalysts, Chem. Mater. 14(5), 1961—1973 (2002). 

The first, made by Ichikawa et al. [29], was the evidence that rhodium or iridium cluster carbonyls, when adsorbed on zinc oxide, titania, lanthanum oxides, zirconia or magnesia, could produce quite selectively ethanol by the Fischer-Tropsch synthesis. This was a timely discovery (metallic catalytic particles produced by traditional methods could not reproduce such selectivity) since it came at a period of geopolitical tension after the Kippur war in 1973, which caused the price of crude oil to increase enormously. Therefore, that period was characterized by intense research into selective Fischer-Tropsch catalysis. 

The advantage of template synthesis is that organo or hydrogelator templates can direct the shape-controlled synthesis of oxide nanotubes. Recent reports describe the use of carbon nanofibers as a template for the shape-controlled synthesis of zirconia, alumina and silica nanotubes [78]. The shape of vapor grown carbon nanofiber... 

Isosynthesis is a potentially important variation of the Fischer-Tropsch synthesis since it yields mainly branched C4-C8 paraffins.187,188 279 280 Most of the pioneer-ing work was carried out by Pichler and coworkers. They observed that certain nonreducible tetravalent oxides (thoria, zirconia, ceria) exhibited activity in the reaction producing primarily isobutane. The optimum operating conditions... 

SYNTHESIS AND CHARACTERIZATION OF POLY (MAGNESIUM ACRYLATE) AND POLY(ZIRCONYL ACRYLATE) TOWARDS THE FORMATION OF MAGNESIUM PARTIALLY STABILIZED ZIRCONIA CERAMICS... 

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