Controllable Synthesis Of Organometal-drived Cobaltosic Composite Metal Oxides And Their CO Catalytic Property

With the rapid development of the national economy,the air condition has become an increasingly important threat to people's quality of life and health.The automobile exhaust,as an important factor affecting the air condition,has increasingly attracted the attention of more and more people.For the elimination of COx and NOx,the main pollutants in exhaust gas,the development of a cost-effective vehicle exhaust catalyst is considered as one of the most effective and feasible methods.Although precious metal catalysts have been proven to have excellent catalytic effects on automotive exhaust gas purification,due to their own low reserves,high prices,and poor stability,new types of catalysts that use non-precious metal components as active ingredients have been developed.Experimental results in recent decades have demonstrated that transition metal oxides(CuOx,FeOx,CoOx,NiO,and MnOx)can exhibit good catalytic performance and are therefore considered viable alternatives to precious metals.In this paper,the research focus on the modification of inner structures in order to develop the novel Co3O4 based materials with controllable morphologies and superior catalytic activities,including hierarchical porous materials,multicomponent composites with the guest transition metal ions.Compared with pure Co3O4 catalysts,the multicomponent composites show the better catalytic performance.The synergistic effect between Co-Ni and Co-Ce was studied by TPR,XPS,XRD etc.The achievements are as follows:In chapter 2 and 3,the multi-structure Co-Ni multicomponent composites have been synthesized by self-assemble mould board method,and the synthesis mechanism and the property of Co-Ni multicomponent composites have been investigated by XRD.TEM?TPR?Raman ? XPS.It can be found that there was strong synergistic effect between Co-Ni components,and the new oxygen species can be found in Co-Ni multicomponent composites,which could be due to the lattice distortion after the incorporation of Ni2+.On the other hand,the synthesis of multi-structure nano-materials further promote the synergistic effect between Co-Ni components,which is the key to enhance the catalytic performance of multicomponent composites.Based on the previous research,the ZIF-67 was proved as a good template to synthesize catalysts.To reserve its high surface area,multistage pore structure,ordered crystal and chemical stability,the CeO2 hollow spheres was used as framework to support the structure of ZIF-67 templates.On the other hand,the CeO2 hollow spheres was encapsulated by ZIF-67,which could also promote the generation of oxygen vacancy and surface defect.