Catalytic oxidation of benzene over CuO/Ce1−xMnxO2 catalysts

Ce1−xMnxO2 (x = 0.1–0.6) mixed oxides were used as supports for preparing 7%CuO/Ce1−xMnxO2 catalysts by impregnation, for use in the total oxidation of benzene. At x = 0.1 and 0.2, most of manganese was fixed in the fluorite structure of CeO2 to form a solid solution. When x exceeds 0.3, some of the manganese appeared as well dispersed MnOx. The redox interaction between CuO and Ce0.7Mn0.3O2 facilitated the activation of surface oxygen for the oxidation of benzene. The defective sites of oxygen on the dispersed MnOx also enhanced the adsorption and oxidation of benzene. 7%CuO/Ce0.7Mn0.3O2 catalyst was a good candidate for replacing noble metal catalysts for the removal of benzene in low concentrations at low temperature.

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► Incorporating manganese into CeO2 to form Ce1−xMnxO2 solution increased the mobility of lattice oxygen and considerably improved the performance of Ce1−xMnxO2 and even the catalysts of CuO/Ce1−xMnxO2 in the oxidation of benzene.
► The oxidation of benzene over CuO/Ce1−xMnxO2 proceeded along three paths: (a) benzene that had been adsorbed on Ce0.7Mn0.3O2 was oxidized by the release of oxygen from Ce0.7Mn0.3O2, (b) benzene adsorbed on CuO was oxidized by oxygen that was released from CuO, or (c) benzene adsorbed on CuO was oxidized by oxygen that was released from Ce0.7Mn0.3O2.
► The redox interaction between CuO and Ce0.7Mn0.3O2 facilitated the activation of surface oxygen for reaction. The defective oxygen sites on the dispersed MnOx enhanced the adsorption and oxidation of benzene.