The Study Of Preparation And Catalytic Combustion On Toluene Of Cu-Mn-Ce Ternary Catalysts

In view of the high cost of noble metal,transition metal oxides like copper manganese oxides are often used for catalytic oxidation of volatile organic pollutants?VOCs?.CeO₂ with good oxygen storage capacity adds into copper manganese oxide to form binary or ternary catalysts to improve the catalytic performance.In this paper,Cu-Mn binary catalysts and Cu-Mn-Ce ternary catalysts supported on TiO₂ has been prepared by impregnation method.Effects of Cu/Mn molar ratio and loadings,Cu/Mn/Ce molar ratio and loadings on the crystalline structure and oxygen mobility of the catalysts were characterized by XRD,BET and H2-TPR.Then Cu-Mn-Ce ternary catalysts were prepared by sol-gel method.Effects of calcination temperature on the crystalline structure and oxygen mobility of the catalysts were characterized by XRD,BET and H2-TPR.Their performances for catalytic oxidation of toluene were evaluated in a fixed-bed tubular reactor.And the catalytic activity of catalysts were measured by the catalytic oxidation of toluene.The following conclusions were drawn:1.The Cu-Mn/TiO₂ catalysts prepared by impregnation method form the composite oxide Cu1.4Mn1.6O4 at the calcination temperature of 500 ?.The synergistic effect between copper and manganese improves the catalytic performance.So the Cu-Mn binary catalyst with 1:1 Cu/Mn molar ratio ? 30% Cu/Mn loadings shows the best catalytic activity with lowest reaction temperature?T95 is 277.5 ??.2.The Cu-Mn-Ce ternary catalyst with 1:1:4 Cu/Mn/Ce molar ratio?30%Cu/Mn/Ce loading prepared by imprengnation method shows the best catalytic activity with lowest reaction temperature?T95 is 274.7 ??.The addition of CeO₂ highly dispersing Cu1.4Mn1.6O4 increased the oxygen mobility of catalyst,thereby improves the catalytic performance of the catalyst.At the same time,the catalyst shows a good stablility on275 ? for keeping good conversion and CO₂ selectivity on toluene for 30 days.3.Compared with the Cu-Mn-Ce ternary catalyst with 1:1:4 Cu/Mn/Ce molar ratio?30%Cu/Mn/Ce loading prepared by imprengnation method,the Cu-Mn-Ce ternary catalysts calcined at 500 ?with 1:1:4 Cu/Mn/Ce molar ratio prepared by sol-gel method shows the best catalytic activity with lowest reaction temperature?T95 is 236.2??.The catalyst without supporter has big surface area,and the activity center?CuO?Cu1.4Mn1.6O4?with higher dispersion form more active sites.It improves the performance of the catalysts in the catalytic oxidation of toluene.In addition,the catalyst shows a good stablility on 236 ? for keeping good conversion and CO₂ selectivity on toluene for 30 days.