Effect of preparation method of iron-, copper- containing oxide catalysts on their activity in the reaction of oxidation of carbon monoxide to carbon dioxide

Iron- and copper-containing oxide catalysts have been synthesized by sol-gel technology with autocombustion using organic reagents - citric acid, glycine, urea as a complexing agent and "fuel"; studied their activity in the oxidation of carbon monoxide to dioxide. The obtained samples were characterized by the methods of X-ray powder diffraction, infrared spectroscopy and electronic paramagnetic resonance, the texture characteristics of these samples was determined by measuring the specific surface area. It is shown that, regardless of the preparation method, all synthesized samples are mixtures of iron oxides Fe 2O3, copper CuO, and copper ferrite CuFe2O4. It was found that the nature of the organic reagent affects the catalytic activity of the synthesized catalysts. On a catalyst with a Cu:Fe=1:1 ratio, prepared by the sol-gel method with autocombustion using urea, the complete conversion of CO is achieved at 130°C. The same catalyst, synthesized with citric acid, is active at 250°C and on a catalyst prepared using glycine, complete conversion of CO occurs at a higher temperature of 350°C. It is assumed that the different nature of combustion leads to the formation of different surface morphology and texture, which ultimately determines the catalytic activity. Thus, the most catalytically active sample was obtained using urea as a "fuel" has a higher specific surface area (25 m2 / g) than the other two samples (for the samples obtained with citric acid and glycine, the specific surface area is 9 m2 / g and 5.8 m2 / g, respectively).