The Synthesis And Performance Of New Type H-BN

h-BN is a material which has received considerable attention due to its properties such ashardness, chemical inertness, high thermal conductivity and the capability of hydrogen uptake.The h-BN will emploied well in catalysts and advanced materials and so on. From now on, thereappliocation of h-BN was far below the way since no appropriate method to synthesize h-BNwith high-performance. The h-BN have been synthesized using different methods, such aschemical vapor deposition, arc discharge, ball-milling, laser ablation, carbon nanotubesubstitution reaction and pyrolysis method. Among them, the arc discharge method and chemicalvapor deposition were considered as a method to synthesize BN nonofibers. But it is not cheap tosynthesize h-BN nanofiber with these methods. For synthesize h-BN with high surface, thepopular methods are carbon nanotube substitution reaction and precursor pyrolysis method. Butit is difficult to synthesize suitable precursor economically and purely. For these reasons, thedevelopment for synthesize h-BN with high-performance and the Characterization of these h-BNare very important. It will promote the application of h-BN immediately.Herein, a facile method to synthesize h-BN from a KBH₄ and NH₄Cl was developed. Theeffects were studied which emploied in the reaction. Some conclusions could be concluded afterstudied the synthesize method by XRD, FT-IR, SEM, TEM and so on.1. The h-BN nanofiber with a fire-new polyhedral morphology was synthesized in usingmetallurgic method. Although the mechanism of formation of this new morphology is unclearand most of the high-temperature reactions are difficult to understand, it appears that ourprecursor with facet (pseudo-polyhedron morphology) and the presence of KC1 are crucialfactors.2. For synthesize h-BN with different morphology, a series contrastive experiments wereconducted which without the presence of KCl. The h-BN with different morphology such asnanocrystals (2-6nm) and nanograins (50-100nm) etc. could be synthesized at different reactioncondition and the ratio of precursor and NH₄Cl.3. The mechanisms of growth and the formation of pore in h-BN were studied. Based on theconglomeration disciplinarian of h-BN nanocrystal in high temperature condition, the h-BN withhigh surface area was synthesized successfully. It could be concluded that the conglomeration ofh-BN nanograins could be promoted by the metalligical environment. The h-BN with highsurface are could be synthesized by change the quantity of KCl. This is a facile and economical synthesis method.4. Considering the potential application in catalyst, the h-BN with high surface area wassynthesized in useing a new method. The h-BN synthesized here was loaded by Pt and employedin the oxidation of CO. The experimental results explained that the h-BN was suit as a carrier incatalyst. The catalysts possess an appropriate performance. Contrast with other carrier, the h-BNwas superior for hardness, chemical inertness, high thermal conductivity and so on.