本文關(guān)鍵詞： 介孔碳納米管 鎢納米線 化學(xué)氣相傳輸 納米碳化鎢　出處：《北京科技大學(xué)》2017年博士論文　論文類型：學(xué)位論文

【摘要】：鎢及鎢基材料以其優(yōu)異的性能在工業(yè)、軍事、科研等領(lǐng)域占據(jù)了重要地位。但是,鎢所具有的本征脆性大大制約了其應(yīng)用,而一維線狀納米鎢—鎢納米線(Tungsten Nanowire,Wn)則憑借其所具有的優(yōu)異性能(較高的彈性模量—225±20 GPa、較高的硬度—6.2±1.7 GPa和較高的抗拉強(qiáng)度—27.5～32.8 GPa)被認(rèn)為是鎢及鎢基材料最好的增韌相,并廣泛應(yīng)用于工業(yè)制品、軍工產(chǎn)品的增強(qiáng)相或電子信息產(chǎn)品的部件等。然而,對鎢納米線而言,雖然研究廣泛,制備方法也很多,但是,目前還沒有一種可實(shí)現(xiàn)其大量、形貌可控且無催化劑參與的制備方法。同時,納米碳化鎢材料作為一種重要的工業(yè)催化劑,也很少有制備方法可以實(shí)現(xiàn)其形貌與尺寸的高度可控。而介孔碳納米管(Mesoporous Carbon Nanotubes,mCNTs)具有獨(dú)特的介孔管壁和中空管腔結(jié)構(gòu),該結(jié)構(gòu)使其可以通過管壁的介孔將材料吸附入中空管腔內(nèi),并束縛材料的生長,進(jìn)而獲得線狀形貌的納米材料。因此,mCNTs可以作為理想模板來制備一維納米材料。但是,由于納米碳材料具有本征憎水性,這使mCNTs的應(yīng)用受到了較大限制。因此,本文從鎢納米線的制備需求出發(fā),以mCNTs為模板,在確保模板結(jié)構(gòu)完整性的前提下對其進(jìn)行了親水性修飾研究。在此基礎(chǔ)上,系統(tǒng)地研究了 mCNTs的濕化學(xué)法填充和偏鎢酸銨(AMT)的還原機(jī)理,在無催化劑參與的情況下,制備了形貌可控的鎢納米線,并對其作為塊體鎢增韌相和納米W2C前驅(qū)體的應(yīng)用做了初步研究,主要包括:(1)在不破壞mCNTs管壁基本結(jié)構(gòu)的前提下,分別采用強(qiáng)酸混合液、稀釋硝酸、雙氧水以及雙氧水與氨水的混合液四種氧化改性試劑對介孔碳納米管進(jìn)行了基團(tuán)可控的親水性氧化改性,通過引入羧基和羥基等親水基團(tuán),成功地使介孔碳納米管獲得了親水性;(2)以毛細(xì)管作用為基礎(chǔ),通過對AMT水溶液的性質(zhì)及AMT水溶液對mCNTs的填充進(jìn)行了系統(tǒng)研究,首次實(shí)現(xiàn)了介孔碳納米管的室溫水溶液大量填充,在室溫條件下實(shí)現(xiàn)了 AMT在介孔碳納米管內(nèi)的批量化填充,制得了 AMT納米棒/介孔碳納米管(AMTn/C);(3)采用X-射線衍射分析(XRD)和熱重-質(zhì)譜聯(lián)用分析方法以及場發(fā)射掃描電鏡(FESEM)設(shè)備,詳細(xì)地研究了 AMTn/C中AMT還原為W的還原反應(yīng)過程和還原參數(shù)對產(chǎn)物形貌的影響,提出了無催化劑參與且形貌可控的鎢納米線生長機(jī)理,并實(shí)現(xiàn)了鎢納米線的可批量化制備;(4)首次通過燒結(jié)制備出了摻雜鎢納米線的塊體鎢,結(jié)果表明鎢納米線在燒結(jié)后的鎢塊材料中仍維持其線狀形貌,并且跨越基體晶界,初步性能測試說明鎢納米線可以起到增韌鎢基體的作用。(5)分別以鎢納米線/介孔碳納米管(Wn/C)和鎢納米顆粒/介孔碳納米管(Wnd/C)為前驅(qū)體,通過熱處理得到了兩種納米碳化鎢材料(W2C納米棒和WC納米顆粒),實(shí)現(xiàn)了納米碳化鎢的形貌可控制備,且首次制備出了亞穩(wěn)相W2C的納米棒。并對所得納米碳化鎢材料的類過氧化物酶特性進(jìn)行了檢測,其中W2C的類過氧化物酶特性檢測屬于首次,而且結(jié)果表明W2C具有優(yōu)異的催化性能。
[Abstract]:Tungsten and tungsten based materials for its excellent performance in the industrial, military, scientific research and other fields occupy an important position. However, the brittleness of tungsten has greatly restricted its application, and the one-dimensional nanometer tungsten - tungsten nanowires (Tungsten Nanowire, Wn) by virtue of its excellent performance is higher (the elastic modulus of 225 + 20 GPa, higher hardness - 6.2 + 1.7 GPa and higher tensile strength of 27.5 ~ 32.8 GPa) is considered to be toughened tungsten and tungsten based materials are the best, and is widely used in industrial products, enhance military products or electronic information product components. However, the tungsten nanowires, although extensive research, preparation methods are also many, but there is still no one can achieve its large, controllable morphology and preparation method of the catalyst involved. At the same time, nano tungsten carbide materials as an important industrial catalytic agent, little preparation The highly controllable method can achieve its morphology and size. The mesoporous carbon nanotubes (Mesoporous Carbon, Nanotubes, mCNTs) has a hollow cavity wall and pipe structure of mesoporous structure of the unique, so that it can be through the mesoporous wall material adsorption into hollow cavity, and bound material growth, and to obtain the nano materials linear morphology. Therefore, mCNTs can be used as the ideal templates for preparing one-dimensional nano materials. However, due to the carbon nano material has the intrinsic hydrophobicity, which makes the application of mCNTs are limited. Therefore, the preparation of demand starting from tungsten nanowires, using mCNTs as a template and the study of hydrophilic modification in the premise of ensuring the integrity of the template structure. On this basis, systematically studied the filling wet chemical method mCNTs and ammonium metatungstate (AMT) reduction mechanism, in the absence of catalysts involved in the case, the morphology can be prepared Control of tungsten nanowires, and made a preliminary study on the application of block, as the tungsten precursor and toughened nano W2C mainly includes: (1) without damaging the wall of mCNTs basic structure, using mixed acid, dilute nitric acid, hydrogen peroxide and hydrogen peroxide and ammonia water mixture of four kinds of oxidation modified reagents on the mesoporous carbon nanotubes were modified with hydrophilic groups controlled by oxidation, carboxyl and hydroxyl hydrophilic groups, succeeded in making mesoporous carbon nanotubes obtained hydrophilic; (2) by capillary action as the foundation, through to the AMT solution and AMT solution on properties of filled mCNTs systematically, for the first time solution of mesoporous carbon nanotubes filled with lots of room temperature, at room temperature to achieve the AMT in mesoporous carbon nanotubes in mass filling, prepared AMT Nanorods / mesoporous carbon nanotubes (AMTn/C); (3) by X- The X-ray diffraction analysis (XRD) and thermogravimetry mass spectrometry method and field emission scanning electron microscopy (FESEM), a detailed study of the reduction of AMTn/C in AMT for the effect of reduction reaction of W and reduction of parameters on the morphology, the catalyst participate and controllable morphology of tungsten nanowire growth mechanism, and the tungsten nanowires can be batch preparation; (4) first produced by sintering bulk tungsten doped tungsten nanowires, the results show that the linear morphology remains of tungsten block material tungsten nanowires after sintering, and across grain boundaries, the preliminary performance test shows that tungsten nanowires can to the toughening effect. The tungsten matrix (5) respectively with tungsten nanowires / mesoporous carbon nanotubes (Wn/C) and tungsten nanoparticle / mesoporous carbon nanotubes (Wnd/C) as the precursor by heat treatment and obtained two kinds of nano tungsten carbide materials (W2C nanorods and WC nanoparticles), real 鐜頒簡綰崇背紕沖寲閽ㄧ殑褰㈣矊鍙帶鍒跺,涓旈嬈″埗澶囧嚭浜嗕簹紼崇浉W2C鐨勭撼綾蟲.騫跺鎵，

本文編號：1502397