The Modification By Doping And Thermal Stability Of Cu-Mn-Ce Mixed Oxide Catalysts

Catalytic combustion is considered to be an efficient technology for the abatement of volatile organic compounds. In general, supported nobel metal catalysts exhibit high catalytic activities at lower temperature, and have been widely applied in industrialized VOCs elimination. However, these catalysts are expensive, sensitive to poisons. In this dissertation, Cu-Mn-Ce oxide was studied systematically by doping noble metal Pt and non-noble metal oxides to improve their catalytic combustion performance and thermal stability. Conclusions were listed as follows:Noble metal Pt-doped Cu-Mn-Ce catalysts were synthesized by the sol-gel method, These catalysts were characterized by XRD, BET, H2-TPR, Raman and their catalytic combustion activities of toluene were tested for the catalytic combustion of toluene. The results indicated that there are many crystalline defects appear in the structure of Pt-doped catalysts, which would be favorable for increase of surface oxygen, leading to better oxidation-reduction ability of catalysts. The activity tests showed that addition of a little of Pt-doping can improve significantly catalytic combustion activity and thermal stability of the mixed oxide catalysts. Secondly, Cordierite ceramic honeycomb-type0.5%Pt-doped Cu-Mn-Ce were prepared by in-situ combustion synthesis technology. Results show that the catalysts exhibited good catalytic activity and thermal stability on various VOCs, especially it is more suitable for catalytic combustion of aromatic VOCs. The catalytic performances of0.5%Pt-Cu1Mn2Ce4/CH is better than commercial Pd catalysts.Finally, non-noble metal (Zr、Y、Al、Si)-doped Cu-Mn-Ce catalysts were synthesized similarly by the sol-gel method, These catalysts were characterized by XRD, BET, H2-TPR. The results indicated that it is helpful to prevent the sintering of crystalline phase and reduction of the crystalline defects in the catalysts calcinated at high temperature by doping Zr and Y, leading to better oxidation-reduction ability of catalysts. The activity tests showed that the proportional addition of Zr and Y in the catalyst exhibited the best catalytic performance and thermal stability.