Activity of 5% CuO/Ce1 \n – \n xPrxOy Catalysts in the Reaction of Carbon Monoxide Oxidation with Oxygen in an Excess of Hydrogen

Abstract

Abstract The 5% CuO/Ce 1 – \xa0 x Pr x O y catalysts were synthesized on the basis of CeO 2 and PrO 2 oxides and Ce 1\xa0– \xa0 x Pr x O y solid solutions with x = 0.2, 0.5, and 0.8. Highly dispersed copper oxide was present in the 5%CuO/Ce 1\xa0– \xa0 x Pr x O y catalysts. Upon interaction with the support, it formed active oxygen, which participated in CO chemisorption and a low-temperature reaction of CO oxidation in the presence of hydrogen. The highest conversion of CO in an excess of H 2 (γ mах ( Т )), which was close to 100%, was obtained at temperatures of 120–160°C on a 5% CuO/CeO 2 catalyst. Upon the modification of CeO 2 with Pr cations, 5% Ce 0.2 Pr 0.8 O y sample, it decreased to 65% at 220°C due to an increase in the bond strength of oxygen in copper-containing centers. A maximum conversion of CO (93%) on a sample of 5% CuO/PrO y was detected at 200°C. Upon the modification of PrO 2 with Ce cations, the activity of 5% CuO/Ce 0.5 Pr 0 . 5 O y and 5% CuO/Ce 0.2 Pr 0.8 O y catalysts did not exceed that of 5% CuO/PrO y . The forms of CO and CO 2 adsorption on 5% CuO/Ce 1\xa0– x Pr x O y samples were studied using the TPD method. In a range of 170–500°C, the desorption of oxygen from the supports of 5% CuO/Ce 0.5 Pr 0.5 O y and 5% CuO/PrO y samples was observed. The occurrence of the reaction on 5% CuO/Ce 1 – x Pr x O y catalysts was discussed. With consideration for the properties of CO complexes formed on copper-containing oxidation and adsorption centers, their participation in the reaction of low-temperature oxidation in hydrogen was examined.