Meso-structure Controlled Synthesis And Characteristics Of Copper-Manganese Mixed Oxides Catalyst

Cu-Mn mixed oxide present high activity for many reactions, which catalytic performance is determined on the preparation method and preparation process.In this thesis,Cu-Mn mixed oxide were prepared by co-precipitation altering anion of metal salts. The effects of anion on structure and catalytic performance for water gas shift reaction (WGSR) of copper-manganese mixed oxides were investigated by XRD, TPR, Low temperature N2 adsorption/desorption and SEM. The results denote that texture stability and catalytic for WGSR of samples prepared with acetate is far better than that of sample prepared with sulphate. The samples prepared with sulphate were consituted with mixture of Cu4SO4(OH)6·H2O and Mn3O4. After calcination, Cu4SO4(OH)6·H2O and Mn3O4 transferred to spinel Cu1.5Mn1.5O4, and then Cu1.5Mn1.5O4 is deoxidized to nonuniformly distribution Cu and MnO experienced water gas shift reaction. Unstable texture structure leads to Cu particle sintering and follows deteriorateded catalytic property. On the contrary, the samples prepared with acetate form Cu2+1O and Mn3O4, which is transfered to spinel Cu1.5Mn1.5O4 through calcinations. Cu1.5Mn1.5O4 is reduced to the mixture phase of copper and MnO in which Cu high homogeneous dispersed in MnO. Ion synergistic effect greatly increases thermal stability and catalytic performance for WGSR.The particle size of Cu1.5Mn1.5O4 prepared with acetate increase with calcined temperature from 550℃to 800℃and the phase Cu1.5Mn1.5O4 converted into Cu1.4Mn1.6O4, CuMnO2 at 1000℃. The special surface areas and pore volume decrease, copper-manganese mixed oxides calcined at 1000℃present thermal stability and catalytic performance for WGSR.The deoxidization behavior of the Cu-Mn mixed oxide was tested under different deoxidization atmosphere. In four deoxidization atmosphere, solid solution Cu1.5Mn1.5O4 converted into the mixture phase of copper and MnO with difference texture. Experienced deoxidization process, all the special surface area and pore volume of samples decrease. The mixture atmosphere of CO, CO2, N2, H2 and H2O is the suitable deoxidization atmosphere which lead to more higher Cu dispersion in MnO. Green-rust of iron oxides with Al3+/Fe3+were prepared by coprecipitation in air and N2 atmosphere and characterized by XRD and BET. The experiment outcome indicated Layered Double Hydroxide of green rust structure with Fe2+/Fe3+ and Fe2+/Fe3+/ Al3+ can be obtained in N2 atomosphere.