Catalytic wet air oxidation of acetic acid over different ruthenium catalysts

Ruthenium catalysts were prepared by impregnation of different supports: ZrO2, CeO2, TiO2, ZrO2–CeO2 and TiO2–CeO2. Their activities for acetic acid oxidation in aqueous solution were investigated in a stirred reactor at a reaction temperature of 200 °C and total pressure of 4 MPa. The order of the catalyst activity obtained was RuO2/ZrO2–CeO2 > RuO2/CeO2 > RuO2/TiO2–CeO2 > RuO2/ZrO2 > RuO2/TiO2, which corresponds to surface concentration of non-lattice oxygen (defect-oxide or hydroxyl-like group) of these catalysts. The non-lattice oxygen on the catalyst surface plays an important role in the catalytic activity.