Catalytic degradation of toluene over Cu-Mn-Ce-Zr/TiO₂ coupled with low temperature plasma

A series of supported Cu_xMn_1-xCe_0.75Zr_0.25/TiO₂ (x = 1.0, 0.75, 0.5, 0.25, 0) catalysts were prepared by impregnation and characterized by XRD, H₂-TPR, O₂-TPD and XPS; the performance of Cu_xMn_1-xCe_0.75Zr_0.25/TiO₂ catalysts in the degradation of toluene coupled with low temperature plasma under high space velocity was then investigated. The results indicate that the composite catalysts with single Cu or Mn as the main active component exhibit higher activity than those with double Cu and Mn components; the addition of second component may weaken the interaction between Cu and Ce, leading to a decrease in the content of lattice oxygen and the reducibility at low temperature. The CuCe_0.75Zr_0.25/TiO₂ catalyst exhibits superior performance for toluene oxidation in the initial reaction stage, owing to its high content of lattice oxygen and oxygen vacancies. With the increase of the specific energy density (SED) of low temperature plasma, the concentration of O₃ increases and the MnCe_0.75Zr_0.25/TiO₂ catalyst then displays higher activity in toluene degradation than CuCe_0.75Zr_0.25/TiO₂, because of the prominent enhancement of synergistic effect between plasma and catalyst over the former MnCe_0.75Zr_0.25/TiO₂ catalyst.