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Připrava katalyzátoru MoO3/TiO2 s "eggshell" a rovnoměrnou distribucí Mo metodou vodou asistovaného rozprostíráni MoO3.
Gulková, Daniela ; Kaluža, Luděk ; Vít, Zdeněk ; Zdražil, Miroslav
MoO3/TiO2 is commonly prepared by impregnation of TiO2 with a solution of (NH4)6Mo7O24 followed by calcination to remove ammonia. In the present work we used a new method called solvent-assisted (water-assisted) spreading. We have previously used the method of water-assisted spreading for the preparation of MoO3 on alumina and active carbon. The support reacts with MoO3/H2O slurry. The solubility of MoO3 is low but sufficient for the gradual dissolution and adsorption of Mo species on the support surface. The pH of MoO3/H2O (2-2.8) is lower than the point of zero charge of alumina (6-8) and of active carbon (7-8). The support surface is positively charged and this promotes adsorption of molybdenum-containing anions. The adsorption is very strong and catalysts with deep, sharp eggshell profiles of the Mo concentration are obtained. In the present work we have applied this method to the MoO3/TiO2 system.
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Nanášení CoO a NiO na nosičové monovrstevné MoO3 katalyzátory suspenzní impregnací
Kaluža, Luděk ; Zdražil, Miroslav
The contribution is focused on CoO(NiO) deposition onto supported monolayer MoO3 catalysts applying the principles of slurry impregnation method. Various Co and Ni compounds in their aqueous slurries were tested for reaction with the MoO3 catalysts. The Co(Ni) compounds used were characterized by measuring of their PZC and XRD. The CoO(NiO) deposition on MoO3/Al2O3 extrudates was evaluated using electron probe microanalysis, EPMA. Deposited CoO (NiO) species was found to significantly enhance the activity of the supported MoO3 catalysts in hydrodesulfurization, HDS, of benzothiophene. The activity of the catalysts prepared was comparable with the activity of the reference commercial catalysts.
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