The purpose of preparation and characterization of boron nitride nanomaterials is to improve the properties of traditional boron nitride materials, give full play to their various effects at the nanoscale level, achieve expected excellent properties and expand new application fields. 1, boron nitride coating has obvious chemical inertia at high temperature, so that boron nitride coating can be used to protect aluminum, magnesium, zinc alloy and other materials from high temperature oxidation. When coated with refractory or ceramic ware, the boron nitride coating can effectively protect it against oxidation even at temperatures up to 1273K. Figure 6 shows a tool coated with boron nitride.
2. The high thermal conductivity of BN has always been a passion of scientific research workers. It is mainly used to prepare composite materials with high thermal conductivity of nano-H-BN and C-BN to accelerate heat dissipation and heat conduction. Fig. 7 shows the thermal conductivity mechanism of boron nitride nanosheet composites. At the same time, it can solve the problem of avoiding short circuit when the thermal conductive material is in contact with the electrical parts in operation and the high resistivity material is needed. BN is more suitable for the thermal conductive material than carbon nanotubes. The thermal conductivity of the composite was as high as 180W/(m·K), which was obtained by blending the ultrasonic stripped two-dimensional boron nitride nanosheets with one-dimensional cellulose nanofibers.
3. Water purification Effectively removing oil, organic solvents and dyes from water is a global problem for water conservation. It is urgent to develop advanced adsorbent materials with excellent adsorption capacity. Using boron trioxide and guanidine hydrochloride as raw materials, it was heated at 1100℃ under N2/H2 mixed carrier gas and kept for 2 hours. The specific surface area of the synthesized boron nitride nanosheets is as high as 1427m2/g, as shown in Figure 8. Its ability to adsorb pollutants such as ethanol, toluene and oil in water is significantly higher than that of commonly used adsorption materials. More interestingly, the porous billet material made from BN nanosheets can absorb oil and simply burn it in the air to remove oil stains. Its enhanced inertia and antioxidant properties make it reusable after oil burns.
4. Hydrogen storage material hydrogen is the cleanest energy at present, which has a bright development prospect for solving the problem of air pollution. How to use and store hydrogen safely and effectively is the primary problem for researchers to solve. Porous BN nanoribbon was prepared with melamine and boric acid as precursors at 900-1100℃. The specific surface area of BN nanoribbon was up to 1488m2/g, which is the largest in the reported BN family, and its hydrogen storage performance is also very excellent. Figure 9 shows the morphology and hydrogen adsorption-desorption curve of BN nanoribbon.
As an advanced nanomaterial and ceramic material, boron nitride nanomaterial has been favored by various fields because of its excellent physical and chemical properties, and will play a more important role in the fields of optoelectronics, environmental protection and daily chemical. Based on the existing research and application, we need to open up new ideas to realize the large-scale, economical and zero-pollution synthesis of boron nitride nanomaterials and promote their wide application.
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