【作者】 王百年；

【导师】 钱逸泰；

【作者基本信息】 中国科学技术大学 ， 无机化学， 2009， 博士

【摘要】 本论文分别采用高温固相法及低温溶剂热法、气相热解法和溶剂热催化法探索了氮化硅、氮化碳和碳材料等多种纳米结构的合成方法。由于所用原料比较廉价、条件相对温和或者方法简便、产率较高,这几种方法均具有一定的工业应用前景。1、以NaN₃,SiCl₄和Mg粉为原料,在200-350℃温度下于高压釜中合成了结晶良好的α相和β相混合的氮化硅粉体,该反应转化率为54.04%;对上述实验设计了正交实验,得到了合成氮化硅的优化条件;在1 L反应釜中进行了放大实验,反应转化率为50%,表明该方法存在很好的工业应用前景。相关研究工作的成果发表在International journal of applied ceramicstechnology。2、以廉价的硅铁合金和氯化铵为原料,在600℃合成了α相的氮化硅纳米线束,单根纳米线直径8 nm,长达800 nm,考察了反应温度和反应时间对产物纯度和形貌的影响;以硅粉和铁粉为原料合成了纯度良好,直径为150～500 nm的α-Si₃N₄亚微粒子;以硅粉和铝粉为原料在400-600℃合成了直径为10 nm左右的α相氮化硅纳米线束。由于所用原料均为较廉价的工业产品,该合成方法存在一定的工业应用前景。3、在400℃下,以三聚氰胺和镁为原料,通过热解反应制备了石墨相氮化碳纳米线束;以纳米线束为前躯体,550℃煅烧后得到长度约为几个微米,管径500-800 nm的六方氮化碳纳米管和氮化碳片状阵列。与其他方法相比,该方法步骤简单、条件温和,得到的氮化碳形貌新颖,为氮化碳材料的制备提供了一条思路。相关研究工作的成果发表在高等学校化学研究4、以四氢呋喃为反应原料,以铁粉和镍粉为催化剂,通过溶剂热催化方法在500℃一步合成了平均直径为100 nm,长度达10μm以上的纳米碳纤维;以乙醇为原料,以NaBH₄为催化还原剂,在500℃一步合成出具有独特“烟斗状”形貌,直径约1μm,长度达10μm以上的碳胶囊。由于步骤简便和较高的产率,本方法经过进一步研究可以应用于一维碳材料的规模生产。相关研究工作的成果发表在无机化学学报（英文版）更多还原

【Abstract】 This dissertation concentrates on the synthesis of silicon nitride,carbon nitride and carbon nanostructures through solid phase reaction,solvothermal route at low temperature,thermolysis and solvothermal catalytic methods.As the reactant is very cheap and the reaction condition is mild,these methods are promising in industrial application to some extent.1.The mixtures ofα- andβ-Si₃N₄ nano-crystalline were prepared in 200-350℃using NAN₃,SiCl₄ and Mg powder as the starting materials.The conversion ratio was 54.04%calculated from the amount of limited reactant NAN₃. Orthogonal strategy was performed to find the optimized reaction condition. Magnified experiments were carried out in a 1000 ml autoclave.The conversion ratio was about 50%which indicated that it was a promising process in industrial application.2.Starting from ferro-silicone alloy brezee and ammonium chloride,α-Si₃N₄ nanowires bundles have been obtained at 600℃.The nanowires have about 8 nm in diameter,up to 800 nm in length.The influence of reaction time and temperature on the products was investigated.Using silicon and metallic iron,α-Si₃N₄ olivary microparticles with a diameter of about 300～500 nm have been obtained at 650℃.When silicon and metallic aluminium were used to react with ammonium chloride,α-Si₃N₄ nanowire bundles with diameter of about 8 nm can be also obtained at 600℃.Since all of the starting materials used are relatively cheap,the methods will have potential prospect in industrial application.3.Graphite-like carbon nitride nanowire bundles with diameters of 200-500 nm were synthesized from the solid state thermolysis of melamine at relatively low temperature（400℃）.Hexagonal carbon nitride tubes with diameters of 500-800 nm and flake arrays were prepared by heating the nanowire bundles at 550℃in argon atmosphere.The products were characterized in detail and the forming process of tubes and transformation of the molecular structures from s-triazine rings to tri-s-triazine units was analyzed.Compared with other methods,it provides a new simple and mild route for synthesis of carbon nitride with new morphology.4.Carbon nanofibers have been prepared through a simple catalytic route using tetrahydrofuran as the solvent and carbon source,Fe and Ni as catalyst,at 500℃. The carbon nanofibers have the average diameter of 100 nm and lengths ranging from hundreds of nanometers to several micrometers.Carbon micro-capsules with morphology of tobacco pipe have been synthesized through a catalytic solvothermal approach using ethanol as the solvent and carbon source,sodium borohydride as catalyst,at 500℃.The as-prepared carbon micro-capsules have the average diameter of 1μm and lengths of over ten micrometers.Due to the simplicity and large-scale synthesis,this work may have an opportunity to be applied in industrial production of one-demention carbon materials.更多还原