Fabrication Of Supported Metal Catalysts And Investigation Of Catalytic Performance

The catalysts have been widely used in various fields,such as petroleum refining,pharmacy,and waste treatment,etc.Most of the catalysts are pure metals and alloys.However,the nanosized catalysts could be easily sintered and agglomerated.Therefore,substrate-supported strategies are developed to avoid these problems and improve the atomic utilization rate of the catalysts.In this thesis,three types of substratesupported metal catalysts were prepared,and their catalytic properties were studied.The main contents and conclusions are listed as follows.1.Polystyrene@silver core-shell structured(Ag@PS)catalyst was prepared through in situ reduction via flash nanoprecipitation(FNP).The particle size of Ag@PS composites shows good uniformity.The silver nanoparticles were well-dispersed on the surface of polystyrene microspheres,which effectively prevented their agglomeration and increased the specific surface area of the catalytic species.The results in catalytic experiments showed microparticles have high catalytic performance and good reproducibility for the reduction of 4-nitrophenol.2.Co,Zn metal-organic framework precursors were prepared by solvothermal method.The Co-NC catalysts obtained by high temperature carbonization delivered porous structure and high specific surface area,large proportion of active nitrogen species and graphitized carbon.When used as the catalysts for methanol conversion,the materials show high catalytic activity towards methanol oxidation,excellent stability and immunity to methanol conversion in alkaline solution.3.Fe,Co,Zn metal-organic framework precursors were prepared by solvothermal method,and FeCo-NC catalysts were obtained after carbonization at high temperature.The catalytic performance of different amount of Fe additives was systematically investigated.It was found that the graphitization degree of the catalyst was increased after the addition of Fe in the solution.At the same time,the oxygen reduction peak,the limit current,the half-wave potential and the starting point of the catalyst are greatly improved.When the addition ratio of Fe/Co is 11,it gets the best performance.The materials showed good catalytic activity,superb cycling stability and methanol resistance in both alkaline solution and acidic electrolyte.