Controllable Synthesis And Thermo-catalytic Ammonia Decomposition Performances Of Supported Ru Catalysts By "Saccharide-urea Derivative-metal Salt" Method

In recent years,it is the increasingly serious problems of environment and energy.The development and utilization of new energy sources is urgent for researchers.As a clean and pollution-free secondary energy source,hydrogen energy has attracted people's attention for the advantages,such as cleanness,high efficiency and no pollution.The ammonia decomposition technology is an ideal solution for hydrogen production.It is of great significance and application prospect to develop an ideal catalyst for ammonia decomposition to improve its low temperature catalytic activity.However,the traditional impregnation method for preparing nano-materials is easier to bring the agglomerate in the preparation process,which is a common and urgent problem to be solved.In this thesis,a series of composite catalysts were prepared by a simple synthesis method and used for the ammonia decomposition reaction.Through the analysis of the structure,carrier,active component and catalytic activity of the prepared catalyst,the influencing factors affecting the catalytic activity of the reaction system were discussed,and the related laws and conclusions were summarized.The main work of this paper is as follows:1.Using silica sol,antimony trichloride,glucose and urea as precursors,microwaveassisted irradiation was used to prepare silica-supported ruthenium catalyst.The carbon template was removed by high temperature in air,and ruthenium nanoparticles could be dispersed on the carrier silica uniformly.The prepared catalyst shown excellent ammonia decomposition catalytic activity than the impregnation method.The superiority is manifested in the uniformity of the distribution of nanoparticles.thereby the catalytic activity and stability of the catalyst was improved.2.Further studied,changing the size of the carrier silica,changing the corresponding conditions in the preparation process,increasing the carbon content of the catalyst,etc.,a series of composite catalysts were prepared,and the properties and catalytic activities of the composite catalyst were discussed.The results show that the size and carbon content of the carrier have a great influence on the size of the nanoparticles and the adsorption and desorption of the substrate of the reaction product,further changing the catalytic activity of the catalyst.3.Using glucose,urea and nickel nitrate as raw materials,a series of Ni-C catalysts were prepared assisted-microwave irradiation under the eutectic system of sugar-urea-salt system.The specific surface area and sizes can be controlled by changing the temperature and conditions of subsequent heat treatment.Meanwhile,the carbon-supported nickel catalyst was evaluated for its ammonia decomposition activity.The results show that catalysts own a small specific surface area have the higher ammonia decomposition activity.