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Titania Supported Co-Mn-Al Catalysts in Total Oxidation of Ethanol
Ludvíková, Jana ; Jirátová, Květa ; Klempa, Jan
In pelletized mixed oxide catalysts prepared by calcination of coprecipitated precursors, a considerable part of the pellets is not utilized in case of very fast catalytic reaction, due to the effect of internal and external diffusion. Therefore, deposition of thin active layer on a supporting material is advantageous. In this contribution, the effect of the support (titania grains and extrudates) on properties and catalytic activity in VOC oxidation of both catalyst geometric forms were examined.
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Photocatalytic niobium and tantallum doped monodispersed nanoparticles of titania for visible-ligt applications
Štengl, Václav ; Houšková, Vendula ; Bakardjieva, Snejana ; Murafa, Nataliya
Niobium or tantalum doped anatase were prepared by thermal hydrolysis of peroxotitanium complex aqueous solutions dissolving niobium or tantalum peroxo-comples at 100 degrees C for 3 days The synthesized samples were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), High Resolution Transmission Electron Microscopy (HRTEM), surface area (BET) and porosity determination (BJH) The photocatalytic activity of doped titania samples was determined by decomposition of salicylic acid during irradiation at 365 nm and 400 nm Niobium-doping caused the increase of unit cell constants of anatase and the shape change of anatase crystallites from spindle-like to cubic-like structure. The niobium and tantalum doping increases the stability of anatase to above 1000 degrees C by inhibiting the growth of Mania crystallites.
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