Study On Preparation Technology Of Two-dimensional Hydrogen Boride Nanosheets

Since the advent of graphene in 2004,its unique two-dimensional hexagonal honeycomb crystal structure has given it excellent electronic,optical and mechanical properties.The discovery of graphene promotes the development of two-dimensional materials.The synthesis methods and practical applications of two-dimensional materials in other fields have become the research hotspot of researchers.Most of the existing two-dimensional materials are separated from layered materials,and the main preparation methods are mechanical stripping method,liquid phase stripping method etc.Which greatly limits the discovery of new two-dimensional materials.In this paper,the top-down synthesis method cation exchange method was used to prepare two-dimensional HB nanomaterials,and a series of characterization methods were used to prove that the synthesized samples were HB nanosheets.First of all,in order to explore the best conditions of synthesis method,the content of raw material magnesium diboride was 100 mg,200 mg,300 mg,400 mg four groups of control test,and the best content was 200 mg;then the polar solvent was discussed,and the best reaction solvent was polar aprotic solvent acetonitrile.SEM was used to characterize the morphology of the synthesized samples.Secondly,XRD,EDS,TEM,FTIR,Raman,XPS and other analytical methods were used for qualitative analysis of the samples synthesized under the optimal conditions.It was found that the synthesized samples contained two substances,boric acid(H₃BO₃)and HB.Finally,the reason of boric acid production was described and the process was optimized.Most of the by-product boric acid was separated,and high-quality HB nanosheets with better morphology,more uniform size,thickness of about 30nm and higher content were obtained.The obtained HB monolayer sheet can be folded and bent under TEM lens,showing good flexibility.At the same time,TG-DTA was used to analyze the thermal properties of the synthesized samples,which showed that the content of boric acid was greatly reduced after the optimization of the process,and the exothermic peak of HB was found at about250?.The thermal analysis showed that HB could be used as an energetic material like other borohydride compounds,and the products after combustion of HB were non-toxic and harmless,and would not pollute the environment,so HB could be used as a kind of fuel Clean,non-toxic and pollution-free solid propellant fuel.