Abstract 1
Porous acicular mullite (3Al2O3•2SiO2) is promising material for filtration of diesel engine exhaust. It appears that microstructure consisting of elongated, prism-like, mullite grains efficiently captures carbonaceous matter without causing considerable pressure drop. In order to provide an undisturbed operation of diesel engine it is necessary to continuously remove (oxidize) the captured carbonaceous particles. In this study, it was shown that the reaction of oxidation of carbon particles located in porous mullite can be catalyzed by the presence of Cu3Mo2O9. Mullite containing Cu3Mo2O9 particles was fabricated by novel approach using commercial Al2O3, CuO and powder obtained by controlled oxidation of crushed, waste MoSi2 heating elements. The oxidation of MoSi2 led to the formation of powder mixture consisting of amorphous SiO2 and MoO3. SiO2 reacted with Al2O3 during sintering to form mullite whereas MoO3 partially reacted with CuO to form Cu3Mo2O9 and partially evaporated introducing an additional porosity into mullite material. Effect of sintering temperature as well as the effect of amount of CuO additive on mullite properties were studied. It was found that the increase in amount of CuO decreased porosity and increased compressive strength. The presence of 12 wt% CuO increased the strength up to 70 MPa, whereas porosity was reduced from 63% in pure mullite to 44% in mullite containing 12 vol% CuO. Graphite particles were subsequently introduced into the samples in order to examine the catalytic properties of the obtained mullite material. After heat treatment of mullite samples containing 10 wt% of graphite it was found that the presence of Cu3Mo2O9 in mullite promotes the oxidation of graphite.

Abstract 2
Sphene (CaTiSiO5), a calcium titanosilicate ceramic has been prepared from a powder mixture of CaCO3, TiO2 and SiO2 using vibro-milling for homogenization and activation of precursors. Also, mechanical activation of precursors has been used for the preparation of Cr-doped sphene ceramic pigments (CaTi1−yCrySiO5). The mechanochemical process initially yielded amorphous powders, which on further calcination, crystallized to yield sphene ceramic. Low and high pressure sphene ceramics are obtained by pressureless and high pressure - high temperature synthesis process (at 4 GPa, 1200°C). The resulting room (P21/a) temperature phase is thermally unstable and it transforms to high (A2/a) pressure-temperature phase.
The evolution of the phase composition with thermal treatment was investigated by X-ray powder diffraction (XRPD). Powder morphology and particle size distribution were analyzed by scanning electron microscopy (SEM) and laser diffraction, respectively. Rietveld refinement was employed to get the structural information of the synthesized powder. Densification and microstructure evolution was determined by means of density and scanning electron microscopy (SEM). UV/Vis reflectance spectra are used to determinate the behavior of the chromium ion. The color efficiency of pigments was evaluated by colorimetric analysis (CIE L * a * b system). Raman and IC measurements were performed to verified phase transition.

Abstract 3
Three different techniques (templating, without template and leaching) were applied to obtain mesoporous ceria (CeO2) materials. Synthesis was done in presence of a soft template as well as hard template. As a soft template, a hybrid organic/inorganic route, such as ordered mesoporous carbon (OMC) and carbon sphere were used as a matrix. After infiltration of Ce(NO3)3, carbon template is eliminated by thermal treatment in air. In mesoporous silica SBA-15 as a hard template was infiltrated Ce-sol and heat treated to consolidate ceria layer on template. Silica is removed by chemical treatment. Hydrothermal synthesis method with NaOH was applied for mesoporous ceria without template. These materials were sintered without additives as well as with MgO aid that was leach out by acetic acid at 85 C. These materials were characterized by nitrogen adsorption-desorption measurements, X-ray diffraction and scanning electron microscopy (SEM). It was revealed that samples have high specific surface, developed mesoporosity structure. Porous structure is a function of the Ce/template ratio and could be controlled by concentration of starting solution.