Structure and activity of RuO₂/γ-Al₂O₃ catalyst doped with CeO₂ in wet air oxidation degradation of phenol

RuO₂/γ-Al₂O₃ and RuO₂-CeO₂/γ-Al₂O₃ catalysts were prepared by the impregnation method. The structure of the catalysts was investigated by XRD, XPS and ESR. The catalytic activity was studied in the wet air oxidation (WAO) of phenol. The results show that the dispersion of RuO₂ particles is higher on RuO₂-CeO₂/γ-Al₂O₃ catalyst than that on RuO₂/γ-Al₂O₃ catalyst. There were oxygen deficiencies and chemisorbed oxygen on the surface of the two catalysts. Moreover, the amount of them increased after the addition of CeO₂ into RuO₂/γ-Al₂O₃ catalyst. RuO₂/γ-Al₂O₃ and RuO₂-CeO₂/γ-Al₂O₃ catalysts have a good activity in WAO of phenol. At a mass concentration 4200 mg/L of phenol, 150°C and 3 MPa, phenol was totally removed after 150 min over RuO₂/γ-Al₂O₃ catalysts, and the phenol removal ratio was 96% after a 60 min reaction over RuO₂-CeO₂/γ-Al₂O₃ in WAO.