本文選題：氮化硼 + 納米管　； 參考：《廣西大學(xué)》2015年碩士論文

【摘要】：“低維材料”指的是一類在一個(gè)或多個(gè)維度處在納米尺度范圍內(nèi)的新型材料,零維富勒烯、一維納米管和二維納米片就是這類材料的典型代表。與塊體材料相比,低維材料由于存在量子尺寸效應(yīng)和表面效應(yīng)而展現(xiàn)出許多新的性能。氮化硼納米材料經(jīng)過近二十年的發(fā)展已經(jīng)成為目前最具前景的無機(jī)納米材料體系,低維氮化硼納米材料具有極好的機(jī)械硬度、寬光學(xué)帶隙、強(qiáng)紫外光發(fā)射、高熱導(dǎo)率、卓越的熱穩(wěn)定性和化學(xué)惰性,在未來光電子、激光、場致發(fā)射、功能復(fù)合材料等應(yīng)用上擔(dān)當(dāng)十分關(guān)鍵的角色。目前,氮化硼納米管已通過多種合成方法成功制備,如電弧放電法、化學(xué)氣相沉積法、固相法等,氮化硼納米片也通過微機(jī)械處理法、化學(xué)溶劑剝離法、化學(xué)氣相沉積法等被成功獲得。但是這些方法或多或少的存在原料不安全、產(chǎn)量低、能耗大、形貌差等缺陷。本文在綜述近年國內(nèi)外對(duì)氮化硼納米管和納米片研究進(jìn)展的基礎(chǔ)上,采用工藝條件簡單高效的固相反應(yīng)法成功合成出高產(chǎn)量高純度的氮化硼納米管,并首次成功合成出由大量氮化硼納米片組裝而成的微米線,這是一種從未被報(bào)道的新型氮化硼微納米結(jié)構(gòu)。本文選用無定形硼粉為硼源、六水合氯化鐵為催化劑、氨氣為氮源,按催化劑與硼源摩爾比為0.05：1混合原料,在1200℃下與50 mL·min-1的流動(dòng)氨氣發(fā)生氮化反應(yīng)5 h,得到高產(chǎn)量高純度的竹節(jié)狀氮化硼納米管和由氮化硼納米片組裝而成的微米線,納米管和微米線的直徑均勻,平均直徑分別約為90nm和2μm,微米線上的納米片厚度低于20nm。其中,氯化鐵甚少被報(bào)道用于催化氮化硼納米管生長,在本實(shí)驗(yàn)中它不僅作為催化劑,更是反應(yīng)歷程中十分關(guān)鍵的反應(yīng)物,能將固態(tài)硼源轉(zhuǎn)化為中間態(tài)含硼氣體。同時(shí)本文還研究了不同工藝條件對(duì)產(chǎn)物的影響,如反應(yīng)溫度、反應(yīng)氣氛、催化劑用量和種類、反應(yīng)時(shí)間等。結(jié)果表明,中間產(chǎn)物氣態(tài)硼源、催化劑小液滴和還原性氣氛是影響氮化硼納米管和微米線生長的關(guān)鍵條件。反應(yīng)溫度偏低、催化劑用量偏少、催化劑種類不同都會(huì)引起氣態(tài)硼源和催化劑熔融小液滴的產(chǎn)量偏低,導(dǎo)致納米管產(chǎn)量下降,微米線直徑變小;不同還原性氣氛中氫含量的多寡直接決定納米管能否生長；反應(yīng)時(shí)間過短會(huì)導(dǎo)致反應(yīng)不完全,進(jìn)而產(chǎn)物產(chǎn)量降低。綜合各項(xiàng)表征數(shù)據(jù)結(jié)果,氮化硼納米管的生長機(jī)制可歸結(jié)為氣-液-固和固-液-固的混合生長模型；氮化硼微米線初期生長是以納米管為生長基體,在其上以氣-固生長模型不斷沉積大量納米片,最終形成由納米片組裝而成的微米線。產(chǎn)物的光致發(fā)光(PL)性能研究表明,氮化硼納米管和微米線分別在354m和357nm波長處出現(xiàn)強(qiáng)的發(fā)光峰。兩種產(chǎn)物的PL曲線對(duì)比顯示,微米線具有遠(yuǎn)遠(yuǎn)高于納米管的紫外發(fā)光強(qiáng)度,顯示出極其優(yōu)異的紫外發(fā)光性能,結(jié)合其微納米結(jié)構(gòu)特性,在光電納米器件中具有潛在的應(yīng)用前景。
[Abstract]:"Low-dimensional material" refers to a new class of materials with one or more dimensions in the nanoscale range. Zero dimensional fullerenes, one-dimensional nanotubes and two-dimensional nanochips are typical examples of such materials.Compared with bulk materials, low dimensional materials exhibit many new properties due to the existence of quantum size effect and surface effect.After nearly 20 years of development, boron nitride nanomaterials have become the most promising inorganic nanomaterials. Low dimensional boron nitride nanomaterials have excellent mechanical hardness, wide optical band gap, strong ultraviolet light emission and high thermal conductivity.Excellent thermal stability and chemical inertia play a key role in the future applications of photoelectron, laser, field emission, functional composites and so on.At present, boron nitride nanotubes have been successfully prepared by a variety of synthetic methods, such as arc discharge, chemical vapor deposition, solid phase method, etc.Chemical vapor deposition was successfully obtained.However, these methods are more or less unsafe raw materials, low production, large energy consumption, poor morphology and other defects.On the basis of a review of recent progress in the research of boron nitride nanotubes and nanoparticles at home and abroad, boron nitride nanotubes with high yield and high purity were successfully synthesized by solid state reaction with simple and efficient process conditions.For the first time, a large number of boron nitride nanowires have been successfully synthesized, which is a new type of boron nitride microstructures that have never been reported.In this paper, amorphous boron powder is used as boron source, ferric chloride hexahydrate as catalyst, ammonia as nitrogen source, and the molar ratio of catalyst to boron source is 0.05: 1.At 1200 鈩，

本文編號(hào)：1750196