ИСТИНА

The aim of this work was to track the influence of the template nature on the catalytic action of CeZrOx (CZ, Ce:Zr=4) and CeSnOx, pristine and modified with MnOx or CuOx. Three types of templates were used: surfactant etyltrimetylammonium chloride (CTAB), polymer Pluronic 123 and biotemplate wood sawdust (SD). CZ [5], Ce0.9Sn0.1O2 and Cu/Ce0.9Sn0.1O2 [2] prepared without template were used for comparison. Modifiers (MnOx or CuOx) were co-precipitated Ce, Zr or Sn oxides; only Mn-CZ-IM catalyst was prepared by subsequent wet impregnation of CZ with Mn acetate solution. Calcination temperature of 500°C was used as providing more defect structure and better catalysts than higher values (e.g. 600°C). CO oxidation was performed in continuous-flow system with fixed-bed of catalyst and pulse feeding of stoichiometric mixture of reagents (2%CO, 1%O2, balance He). Temperature was raised to 400°C with 50°C increments. The catalysts were investigated by XRD which confirmed fluorite structure of mixed CZ or cerium-tin oxides; temperatureprogrammed reduction (TPR) and XPS which revealed the presence and the ratios of Ce3+/Ce4+, Mn2+/Mn3+ and Cu+/Cu2+ in the corresponding systems and the conditions of their reduction