Preparation Of Hydrotalcite-like Catalysts And Their CO Catalytic Oxidation Performance

In this thesis,the preparation process conditions of MgAl hydrotalcite and CuAl hydrotalcite based catalyst materials,Pt-based supported noble metal supported catalyst materials,and the performance of catalysts in CO catalytic oxidation reaction were studied.Hydrotalcite（LDHs）was used as the support and precious metal Pt was used as the main active component.The precious metal Pt was supported on the hydrotalcite support to prepare the supported Pt based catalyst.LDH carriers with different morphologies were prepared from the perspective of investigating the preparation conditions.The catalysts were characterized by XRD,SEM,H₂-TPR,CO₂-TPD,etc.The preparation method,structure,physicochemical properties and the structure-activity relationship among the catalytic activity of the catalysts were studied and discussed.The main conclusions of this thesis are as follows:（1）MgAl hydrotalcite（LDHs）carrier was synthesized by hydrothermal method.The grain size of LDHs was controlled by controlling the hydrothermal temperature.According to the characterization analysis in this thesis,the size of the MgAl-LDH carrier gradually increases with the increase of crystallization temperature.The catalytic activity of Pt/LDH-0 catalyst was the best,and the complete conversion was achieved at 150 ^℃.（2）Caual hydrotalcite（LDHs）carrier was synthesized by hydrothermal method.The grain size and morphology of LDHs were controlled by adjusting the hydrothermal temperature,changing the precipitant,changing the metal ion ratio and changing the concentration of alkali.Through characterization analysis,the best preparation conditions are the hydrothermal temperature of 110 ^℃,hydrothermal time of 12 h,concentration ratio of metal ion to base of 1:1,Cu²⁺:Al³⁺=3:1.（3）By means of FI-TR,H₂-TPR and CO₂-TPD,the results showed that CuAl hydrotalcite material with CO₃^2-intercalation was successfully prepared,and it had two basic centers and reducing properties.（4）The CO catalytic oxidation performance of CuAl hydrotalcite was further studied,CuAl-LDHs supported precious metal Pt was used to oxidize CO,and the performance of Pt/LDH-Ⅲcatalyst was better,almost complete transformation was achieved at 180 ^℃.The products calcined at high temperature were also supported with precious metal Pt for CO oxidation performance.The catalytic activity of Pt/LDO-Ⅰcatalyst was the best,and the complete conversion was achieved at 190 ^℃.