0000000001267928
AUTHOR
E Kraleva
Mechanical treatment of TiO2 and ZrO2 oxide mixtures
The mixed ZrO2–TiO2 system (5–50 wt% of ZrO2) has been studied to investigate the influence of the mechanical treatment on its physicochemical properties depending on the composition, time of milling (5, 10 and 20 min, r.p.m. 82) and temperature (400, 550 and 700 C). Samples were characterized by Raman spectroscopy, X-ray powder diffraction, Scanning Electron Microscopy coupled with Energy Dispersion X-ray analyzer, High Resolution-Transmission Electron Microscopy and nitrogen adsorption porosimetry. Results show that srilankite (TiZrO4) phase has been produced. No influence of the milling time and temperature on the phase composition is observed. The presence of zirconia increases the ther…
Synthesis, Characterization and Catalytic Activity of mesoporous Mn-MCM-41 materials
MCM-41 has been synthesized at two different pH using cetyl-trimethylammonium bromide (CTAB) surfactant as template and adding the silica precursor to aqueous solutions containing CTAB. The obtained solids were calcined at 600 ◦C for 4 h. Mn-MCM-41 powders with different Mn/Si molar ratios were prepared using the incipient wetness method, followed by calcination at 550 ◦C for 5 h. At the end of the impregnation process the powders colour changed from white to brown whose intensity depends on manganese quantity. The materials characterization was performed by X-ray diffraction, N2 adsorption, 29Si Cross Polarization–Magic Angle Spinning NMR, and X-ray Photoelectron Spectroscopy. The effects …