| The light materials consisted of boron, carbon and nitride are attracted much attentions by scientific workers in the new materials field. Boron nitride (BN), as a kind of dielectric materials with high temperature resistance and chemical interness, is used in very wide application field because of its good mechanical and photoelectric properties. Due to the carbon element joined in, boron carbon nitride compound (BCN) possesses the property of semiconductor materials compared with boron nitride. Therefore, BCN owning the advantages of carbon and boron nitride materials will have a more broad application prospects.In this paper, we had improved the synthesis methods of good dispersive hexagonal boron nitride nanomaterials and studied the synthesis mechanism. Also, we studied the influence of copper oxide for the synthesis of boron carbon nitride, and synthesized hexagonal boron carbon nitride nanoparticles, hydrophobic films and porous materials.1. We had synthesized a kind of spherical hexagonal boron nitride nanoparticles with good water dispersion through the high temperature tube furnace method. Using cobalt sesquioxide (Co2O3) as assistant, velocity of carrier gas and other process conditions were to increase the yield of spherical hexagonal boron nitride nanoparticles. The spherical hexagonal BN was characterized by SEM, XRD, FTIR, EDX, BET and Zeta potential. Compared to h-BN synthesized with copper oxide, the yield of h-BN synthesized with H3BO3, NH4C1, KC1 and Co2O3 was increased to 53%, and the mass product was improved by 60%, which maybe because of the existence of Co2O3. The diameter of the nanoparticles is about 30?40 nm, and the surface area is 74.1m2·g-1. The pore volume of the obtained h-BN is 0.35 cm3·g-1. Zeta potentials of h-BN in a pH range of 4?10 varies from-30 to-40 mV. The important intermediate was Co(NH3)5ONOCl2 which was characterized by XRD. The chemical reaction equations and chemical mechanism were provided. The h-BN nanowires and nanoribbon were also observed in these experiments.2. Boron carbon nitride compound was synthesized by melamine instead of ammonia chloride. Through changing the molar ratio of copper oxide to boric acid and reaction time, the spherical h-BCN nanoparticles were synthesized at 950 ? for 4 h with a molar ratio of CuO and H3BO32:1 under the similar synthesis process as former, which have average size of about 40 nm. Also, the hydrophobic h-BCN films were synthesized successfully with the molar ratio of CuO to boric acid 3:1, at 950 ? for 6 h, which have a water contact angle of 144.5°. All the obtained h-BCN materials were characterized by SEM, XRD and FTIR.3. The percentage of carbon in the BCN would increase through increasing the content of melamine. When the molar ratio of melamine to boric acid was 1.6, the surface area of BCN with the high content of carbon was 765 m2·g-1. Controlling the molar ratio of melamine to boric acid to be 1.16, porous hexagonal BCN was obtained by annealing at 600 ? for 2 h, and the surface area was reached 229 m2·g-1. However, pore structure of BCN was damaged after annealing at the same reaction condition when the content of melamine was increased continually. Therefore, the content of carbon increased will improve the surface area of boron carbon nitride. And, boron carbon nitride would anneal to be porous materials with a moderate amount of carbon. |
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