Structural Unit Control In The Nano-Materials And Its Application For CO Catalytic Oxidation

CO(carbon monoxide)is a typically toxic compound and mostly derived from the combustion of fossil fuel and vehicle exhaust.CO oxidation is commonly used as a model reaction in catalysis research,meanwhile it is also the most direct,cheap and effective method to monitoring and elimination of CO gas,which becomes the current hotspot in the environmental chemistry,materials chemistry and analytical chemistry.CO oxidation,especially at lower temperature possesses potential application value in practical applications and daily life,which is is widely applied in gas purification in CO2 lasers,CO detectors,CO antigas masks,tobacco tar reducing,car exhaust absorption and purification,fuel cell and some closed system(plane,submarine and spacecraft etc.).This work mainly focus in anti-sintering and replacement of precious metals in CO catalysts.We put forward the design of "construction unit" and prepare core-shell Au@CeO2 microspheres,sandwich type Au/TiO2 hollow spheres and core-shell A12O3@CuO microspheres,and deeply discuss these three catalysts for CO oxidation.In summary,these works includes the following three parts:1.Preparation of core-shell Au@CeO2 microspheres and the catalytic activity for CO oxidationA new synthetic strategy is adopted for the preparation of core-shell Au@CeO2 microspheres with clear boundaries.Compared with the supported Au/CeO2 catalyst Au@CeO2 catalyst has better catalytic activity and stability for CO oxidation,which attributes to no migrate and sintering of active component Au nanoparticles in the special core-shell structure.2.Preparation of sandwich type Au/TiO2 hollow spheres and the catalytic activity for CO oxidationSilica spheres are used as template to be coated amorphous TiO2 layer by sol-gel method,and Au NPs are sandwiched in the middle of two TiO2 shell.Then hydrothermal treatment crystallizes amorphous TiO2 to anatase and etches silica template,get the sandwich type Au/TiO2 hollow spheres.This catalyst can achieve same catalytic activity level of commercial Au/TiO2 catalyst toward CO oxidation,and stability and sinter-resistance have greatly improved than commercial catalyst,which attributes to Au NPs with smaller size and the limitation of the TiO2 layer in the catalytic process.3.Preparation of core-shell Al2O3@CuO microsperesand the catalytic activity for CO oxidationA simple alcohothermal method is employed to the preparation of core-shell Al2O3@CuO microspheres.Compared to high temperature calcinations in the supported CuO/Al2O3 catalyst,the low temperature alcohothermal method can get smaller CuO particles,which is beneficial to catalytic activity.Without the use of precious metal,this low-cost catalyst can be as good alternative catalyst to noble metal catalysts and realize large-scale industrial applications.