Catalytic properties of copper-manganese mixed oxides supported on SiO2 for benzene oxidation with ozone

Catalytic oxidation of benzene was carried out over SiO2-supported manganese oxides and manganesecontaining mixed oxides at 333-373 K. The catalysts were prepared by impregnation methods from metal nitrate precursor and calcined at 673-873 K. The addition of Cu, Ni, and Fe to Mn oxides suppressed the decrease of benzene oxidation activity and improved the steady state activity for benzene oxidation at 343 K, whereas the addition of Co decreased the activity. The highest activity was obtained for Cu-Mn/SiO2 catalysts with the molar ratio of Cu-Mn 1:1. XRD studies revealed that Cu3Mn3O8 and CuMn2O4 spinel phases were formed in the Cu-Mn/SiO2 catalysts. The catalytic activity of Cu-Mn mixed oxides increased with the increase in their calcination temperature, in accordance with the increase in the spinel type Cu-Mn mixed oxide phases. (C) 2014 Elsevier B.V. All rights reserved.