A series of Zr_xCe_1－xO₂ catalysts were prepared by co-precipitation. They were characterized by BET, XRD and XPS. The catalytic wet air oxidation of acetic acid was carried out with these catalysts. It showed that the Zr_xCe_1－xO₂ catalyst with 1∶9 atomic ratio of zirconium to cerium demonstrated the best activity. At initial chemical oxygen demand (COD) of 5000 mg/L, reaction temperature of 230 ℃ and the pressure of 5 MPa, the removal efficiency of COD was 76% after 120 min. The good activity of this catalyst could be due to adding zirconium into CeO₂ which could increase surface area and concentration of surface defect oxygen of the catalyst. This finally accelerated the formation of HO₂• radical and improved the activity of catalyst.

Key words: catalytic wet air oxidation, acetic acid, Zr_xCe_1－xO₂ catalyst, wastewater treatment