Preparation, Hydrolysis Performance And Transformation Of Ammonia Borane

With the quickly economic development and rapid population growth, energy demand isgrowing which becomes the focusing problem need to be solved. Despite fossil fuels stilloccupy a large proportion in the energy system structure, fossil fuels are non-renewableresource, and bring serious pollution to environment. The resulting serious energy problemis becoming more highlighted. The key factor to solve this problem is to develop new greenenergy which is clean, renewable and low-carbon. This work includes its efficient storageand transformation technology. Hydrogen is a kind of potential alternative energy sourcewith characteristics of environmental friendly and high energy density. But the productionand storage of hydrogen are major barriers which restrict the development of the hydrogeneconomy. In the1950s, Ammonia borane (AB) was synthesized for the first time. Due to itshigh hydrogen content (19.6wt%), AB and the compounds related as a hydrogen storagematerials are widely concerned by researchers. This dissertation addresses the preparationof ammonia borane, characterization of dehydrogenation catalysts of Ni/BN for ammoniaborane aqueous solution, and ammonia borane transformation to boron nitride.1. Ammonium fluoroborate and sodium borohydride were used as reaction startingmaterials and take two-pot synthesis of ammonia borane. Firstly, all the raw materials wereput in a container which also contained dioxane solvent with reflux device. Secondly, arotary evaporation apparatus was used to spin the solvent in order to get solid matter withheating process. In the end, the target product ammonia borane was got. In this process,dioxane could be recycled by rotary evaporation apparatus and repeatedly used for anothersynthesis process. The repetition frequency is considerable. Ammonium fluoroborate as oneof raw materials is used in this synthetic method for the first time. It is simple andeconomical. The product yield is considerable and purity is high (98%).2. A series of catalysts that Ni particles loading on boron nitride nanospheres and rodlikemicrofibers as supporters were formed via chemical impregnation reduction method. Theloading rates of these catalysts are6.8,9.0,9.2,12wt%. These catalysts are used forammonia borane hydrolysis H2-release reaction. The experimental results indicate that thepromotion of loading rate of catalysts lead to the increasing for hydrogen release rate. Inaddition, the influence of temperature on one of the catalysts is studied as well as activation energy of catalyst, enthalpy and entropy.3. Ammonia borane was used as precursor to prepare boron nitride nano materials. Theprepared products of chemical bubbling method are several nanometers thicknessnanosheets by characterization. Different temperatues and protective gases were used totreat ammonia borane, after the process the products are compared.