类竹节状氮掺杂碳纳米管的制备及性能的研究

本文以三聚氰胺（C3N6H6）为原料,通过高温热分解法成功的制备了氮掺杂碳纳米管（N—CNTs）。据SEM和TEM图像显示,所制备的N—CNTs呈竹节状,并且直径和壁厚统一。利用FTIR图谱分析了N—CNTs的结构和官能团组成。同时,对N—CNTs的发光特性进行了研究,发现样品在蓝紫光范围内具有发光特性,这使得其在光学纳米器件方面具有潜在的应用价值。     

负载型催化剂对风化煤制备腐植酸的影响

以自制碳纳米管（CNTs）为载体,制备了负载型催化剂Ce O2/CNTs、Ti O2/CNTs和Ce-Ti-Ox/CNTs,并进行了TEM及XRD表征。以所得样品为催化剂,用于东都风化煤降解制备腐植酸的研究探讨了催化剂用量、反应温度及不同负载型催化剂对风化煤降解制备腐植酸的产率、分子结构及吸光度的影响。结果表明,所用负载型催化剂催化性能明显高于未负载的催化剂,能显著提高腐植酸的产率,而且所得腐植酸分子量较小,吸光度较高,其中Ce—Ti—Ox／CNTs催化效果最为显著,在82℃、煤样与催化剂质量比为1．5g／0.015g条件下可使腐植酸的产率提高到65．43％,表明铈钛活性组分表现出了协同催化效应。     

煤基富勒烯(C_(60))的制备与提纯

<正>富勒烯是除石墨和金刚石外碳的第三种同素异构体,其代表性分子是C_（60）和C_（70）。大量研究成果表明,富勒烯的特殊球形空心分子结构赋予了它许多奇异的物理化学性质,在超导、非线性光学、催化剂等诸多领域显示出十分诱人的应用前景。目前,国内外主要以高纯石墨电极为原料制备富勒烯,由于煤的价格低廉且来源广泛,以煤炭为原料制备富勒烯的研究备受国外学者的关注。本文以冶金焦为原料用电弧法制备富勒烯,研究了实验操作条件及冶金焦性质与富勒烯收率间的关系。粗富勒烯以活性炭为固定相,甲苯为流动相的柱色谱分离提纯,考察了活性炭的孔隙结构及柱色谱的长度对C_（60）纯度和收率的影响。     

由不同碳源合成洋葱状富勒烯

洋葱状富勒烯(onion-likefullerenes:OLFs)可通过各种高含碳物质(如石墨、金刚石及炭黑等)、甲烷、乙炔等有机化合物和碳化硅等含碳的无机化合物的转化来制备.根据不同的碳源,按不同的制备方法介绍了洋葱状富勒烯的研究现状,着重论述了煤基洋葱状富勒烯合成的研究进展,采用射频或微波等离子体法,以煤为原料制备了洋葱状富勒烯,用高分辨透射电镜(HR-TEM)对其形貌、尺寸与结构进行了观察,其外观呈准球状或多面体状,内中空,直径分布较均匀,石墨化程度很高,实现了洋葱状富勒烯的低温合成,在此基础上,结合等离子参数和煤的化学结构,初步探讨了煤基洋葱状富勒烯的生成机理.     

煤基单壁纳米炭管的制备

采用电弧等离子体技术,以铁粉、镍粉或La-Ni混合物为催化剂,由中国煤成功地制备出单壁纳米炭管.综合运用扫描电子显微镜（SEM）、透射电子显微镜（TEM）、能量散射探针（EDX）及激光拉曼光谱等技术对所制得的单壁纳米炭管进行分析表征,发现得到的单壁纳米炭管具有较高的纯度;所制得的煤基单壁纳米炭管的直径与所使用的催化剂有关,以铁粉为催化剂时,单壁炭管的直径处于1.2～2.2nm之间,而以镍粉或La-Ni混合物为催化剂时得到单壁炭管的直径相近,处于1.26～1.50nm之间;与单壁炭管伴生的其他杂质是少量的碳包纳米金属颗粒和微量的源于原料煤中矿物质的Al、Si等杂原子.     

三种催化剂对纳米纤维素尺寸分布的影响

采用激光粒度分析法测定无催化剂和添加催化剂纳米纤维素的尺寸分布,并对电子显微镜观察法与激光粒度分析法测定无催化剂纳米纤维素的尺寸分布进行了分析。结果表明添加间硝基苯磺酸钠（SMS）制备纳米纤维素尺寸分布较均一,体积数均尺寸为312．013m,所对应的尺寸分布宽度为10．8nm。电子显微镜观察法与激光粒度分析法的无催化剂纳米纤维素样品尺寸分布测定结果较接近,电子显微镜观察法表征纳米纤维素直径尺寸分布更具优势。     

以不同沥青焦为原料制备活性炭的特性分析

以沥青焦、煤沥青以及氧化沥青为原料，采用KOH活化法制备高比表面积活性炭。试验分别考察了不同原料及预处理工艺对活性炭孔径分布与比表面积的影响。发现采用不同原料所制备活性炭的孔径分布呈现出正态分布的特点，孔径分布范围介于0～5．0nm之间，峰的位置介于1．0～1．5nm附近。活性炭主要由1-1．5nm范围的微孔构成，大于2nm的中孔很少。在煤沥青不熔化处理过程中，其挥发分与H／C原子比要适中，挥发分过高与过低均不利于制备高比表面积活性炭。     

由脱灰煤制备富勒烯

以 3种高变质程度的中国煤为原料 ,用电弧等离子体蒸发法制备富勒烯 .富勒烯产品的表征采用质谱、紫外光谱和红外光谱等技术 .采用碱法脱灰技术对 3种煤进行脱灰处理 ,考察了脱灰前后煤样的灰分和相应炭棒中碳含量对富勒烯产率的影响 .结果表明 ,由实验所用煤种均可制得富勒烯 .原料煤本身的化学结构和组成对富勒烯的产率有明显影响 ,表现为富勒烯的产率随炭棒中碳含量的增加而增大 .煤中的矿物质对富勒烯的形成有很强的抑制作用 ,表现为富勒烯的产率随原料煤中灰分的增加而降低 ,这一变化趋势通过对介休焦煤进行不同程度的脱灰处理而得到进一步证实.     

超级球形活性炭制备的研究

以煤沥青为主要原料采用悬浮法制备含致孔剂的煤沥青球后进行预氧化、炭化和活化，最终得到沥青基球形活性炭（PSAC）。借助扫描电子显微镜（SEM）和BET测试，所制得的PSAC球形度好、孔径分布范围窄，是一种高性能的炭质吸附材料。探讨了煤沥青球的预氧化、炭化和活化等工艺条件对PSAC的碘、苯和亚甲基蓝吸附值影响规律。结果表明：当分散荆、水溶液和沥青的吡啶溶液体积比为0．1：0．8：1时，适宜的成球温度为90℃、搅拌速度为200rpm及搅拌时间为20min，由此可制备出平均球形度大于0．9和平均粒径为25μm的煤沥青球；将所制备的煤沥青球经过预氧化温度280℃、预氧化时间6小时和炭化温度700℃、炭化时间40min及升温速率5℃／min，KOH与煤沥青的质量比为3：1的条件下，制备出煤沥青基球形活性炭的比表面积为3365m^2／g，碘、苯和亚甲基蓝吸附值分别达到2256mg／g、1068mg／g和390mg／g，微孔径主要集中分布在2～3nm左右的球形活性炭。     

以负载Fe的介孔分子筛为模板合成碳纳米管

以负载Fe的介孔分子筛Fe/MCM-41和Fe/ABW分别为催化剂,乙炔为碳源,采用化学气相沉积法对催化合成碳纳米管(CNTs)进行研究,讨论了反应温度、催化剂种类以及催化剂预处理对CNTs纯度和形貌的影响,通过场发射扫描电子显微镜、高分辨透射电子显微镜和X-射线衍射仪对产物的结构和形貌进行了表征和分析,并对CNTs的生长机理进行了推测.结果表明,在反应温度为700℃,两种不同的催化剂经H2还原后,催化生长出直径均匀(20nm～30nm)且晶化程度较好的CNTs.     

Carbon nanomaterials from eleven caking coals

Carbon nanotubes (CNTs) have been successfully produced from 10 typical Chinese caking-coals using an arc plasma technique. For comparison, one caking coal from New Zealand is also tested. The results show that all coals tested can be used to produce significant quantities of CNTs with fullerenes as by-products. The CNTs are examined using scanning electron microscope and high resolution transmission electron microscope. It has been found that the yields of CNTs are closely related to coal properties. The CNT yield increases as the fixed carbon content in coal increases or as the volatile matter content in coal decreases.     

Onion-like fullerenes synthesis from coal

Onion-like fullerenes (OLFs) were synthesized in high yields from coal by radio frequency plasma. The morphologies and structures of the products were characterized by high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) technique. Results reveal that OLFs can be prepared from coal with high purity. The particles display a clear polyhedral or quasi-spherical morphology with hollow center, having an average diameter ranging from 10 nm to 35 nm and high degree of graphitization.     

以煤炭直接液化残渣为原料制备炭纳米管

以煤炭直接液化残渣为原料,采用直流电弧放电法成功制备出炭纳米管.采用扫描电子显微镜、透射电子显微镜、高分辨透射电镜以及X射线衍射等手段对炭纳米管的形貌和结构进行了表征.结果表明,所得直而长的多壁炭纳米管具有很好的石墨化程度;其长度达几微米,内径约80 nm,外径约120 nm;残留在液化残渣中的黄铁矿及液化过程中产生的磁黄铁矿对炭纳米管的形成有催化作用.     

Endohedral and exohedral hybrids involving fullerenes and carbon nanotubes

Since fullerenes and carbon nanotubes (CNTs) were discovered, these materials have attracted a great deal of attention in the scientific community due to their unique structures and properties. The properties of both carbon allotropes can be modulated by chemical functionalization, and merging fullerenes and CNTs combines the electronic and optical properties of CNTs with the excellent electron acceptor characteristic of fullerenes; moreover, a synergistic effect of these hybrids can be found, as the properties of both the nanotube and the fullerene are affected by the presence of the other. In these hybrids, the fullerene can be located inside (endohedral) or outside (exohedral) the CNT and both types of hybrid have specific features. CNT-fullerene hybrids have been studied for various applications, including photovoltaics, optical limiting and flame retardancy amongst others. This review outlines the progress in research on CNT-fullerene hybrids, including endohedral and exohedral combinations, their properties, functionalization, applications and outlook.     

Dual formation of carpets of large carbon nanofibers and thin crystalline carbon nanotubes from the same catalyst-underlayer system

A dense, micron-tall layer of carbon nanofibers (CNFs) was grown above a layer of carbon nanotubes (CNTs) during the same synthesis using a thick cobalt catalyst (15 nm). The CNFs had large diameters (100 nm) and were amorphous while the CNTs had small diameter (10–20 nm) and were crystalline. Base growth mechanism was at play for both the nanofibers and the nanotubes. High-resolution transmission electron microscopy characterization suggested that the main mechanisms leading to the growth of the two structures were based on the dewetting of the catalyst layer and its subsequent alloying with the Ta underlayer. We can extend these principles to grow diverse carbon nanostructures during the same synthesis using appropriate multilayer thin films for different applications, especially for electrochemical cells and supercapacitors.     

Formation of carbon nanotubes through ethylene decomposition over supported Pt catalysts and silica-coated Pt catalysts

Ethylene decomposition was performed over supported Pt catalysts to fabricate composites of Pt metal nanoparticles and carbon nanotubes (CNTs). All supported Pt catalysts (Pt/carbon black, Pt/CNT, Pt/MgO, Pt/Al₂O₃ and Pt/SiO₂) showed catalytic activity for ethylene decomposition at 973 K to form CNTs. Pt metal particles were found at tips of CNTs. These results indicate that Pt metal particles have catalytic activity for growth of CNTs through hydrocarbon decomposition. A broad range (5-50 nm) of CNT diameters were formed from the use of supported Pt metal catalysts although Pt metal particles in the catalysts before ethylene decomposition were relatively uniform in size (2-5 nm). These results imply that Pt metal particles in the catalysts aggregated during ethylene decomposition at 973 K. Aggregation of Pt metal particles in catalysts during ethylene decomposition could be suppressed by covering catalysts with silica layers that were a few nanometers thick. Silica-coated Pt catalysts showed high activity for ethylene decomposition to form CNTs with uniform diameters (8-10 nm) despite the uniform coverage of Pt metal particles with silica layers.     

Combined catalyst system for preferential growth of few-walled carbon nanotubes

The effect of a combined catalyst system on the synthesis of carbon nanotubes (CNTs) from methane (CH₄) was investigated using molybdenum trioxide (MoO₃) as a conditioning catalyst and molybdenum-doped iron supported on magnesia as the main catalysts. Without the conditioning catalyst, only single-walled CNTs with diameters smaller than 2 nm were formed on the main catalyst. With the conditioning catalyst, double-walled CNTs and few-walled CNTs with larger hollow diameters than 2 nm were produced with much higher yields. The combination of the two kinds of Mo-containing catalyst would more effectively transform CH₄ into reactive species related to the early stage of nanotube formation on the main catalyst, resulting in the increase of the yield, diameter and layer number of the CNTs.     

Fe/洋葱状富勒烯作为润滑油添加剂的摩擦性能

采用化学气相沉积法(CVD)以二茂铁为催化剂,乙炔为碳源制备了Fe/洋葱状富勒烯(Fe/onion-like fullerenes, Fe/OLFs),通过场发射扫描电子显微镜(FESEM)、高分辨透射电镜(HRTEM )和X射线衍射(XRD)分析了Fe/OLFs的晶体结构和形貌。结果表明,所制备的Fe/OLFs是由同心封闭壳层组成的准球形颗粒,其层间距为0.349 nm,与石墨的层间距0.336 nm相接近。在MRS-10A 型四球摩擦试验机上考察了相似文献   

不同碳源制备气相生长炭纤维的研究

综述了几种不同的碳源,如低碳烃(甲烷、丙烯、乙炔和苯等)、脱油沥青、煤沥青,采用化学气相沉积(CVD)法,按不同转化过程制备出气相生长炭纤维(VGCFs)的研究现状.主要研究了以煤沥青为碳源、二茂铁为催化剂,借助CVD法制备气相生长炭纤维.经场发射扫描电子显微镜(FESEM)、高分辨透射电子显微镜(HRTEM)、X-射线衍射(XRD)及拉曼散射(Raman)分析,结果表明:产物主要为高纯度的VGCFs,直径分布均匀,外径大约为100 nm,长度数微米,并初步探讨了煤沥青制备气相生长炭纤维的生长机理.