催化裂解低碳烷烃制备碳纳米管薄膜

碳纳米管性质奇特、用途广泛[1]。目前制备碳纳米管薄膜的方法主要有电弧放电法[2]、催化裂解[3]、及真空过滤碳纳米管悬浮液制备“巴基管纸”(Buckypaper)[4]等。本文采用镀镍基板催化裂解低碳烷烃法制备碳纳米管薄膜,考察了镀膜时间、蚀刻和氨水处理等条件对碳纳米管薄膜产物形貌的影响。1　实验部份1 1　镀膜与后处理采用离子溅射法在硅酸盐基板上镀镍,镀镍电流7 5mA,镀镍时间分别为2min、15min、30min、45min或60min;对镀镍基板再进行蚀刻(蚀刻电流7 5mA,蚀刻时间2min)或用氨水浸泡处理(含NH325%,超声振荡30min),然后烘干备用。1 …     

分叉碳纳米管的催化生长

Branching carbon nanotubes were synthesized by pyrolysis of acetylene at 700℃ over oxygen-free copper and γ-Al₂O₃-supported Cu unitary or Cu/Fe binary catalysts. The morphologies of the as-grown products were charac-terized by transmission electron microscopy. The results indicated that the branching structures were closely related to the Cu component of the catalysts. We proposed that the special electronic structure (3d¹⁰4s¹) of Cu play the crucial role in the formation of the heptagon defects related to the branching structures.     

Ni-Sm-MgO催化热解CO制备碳纳米管

在550～750℃，通过CO在Ni-Sm-MgO催化剂上催化歧化制备了碳纳米管．在Ni-MgO催化剂中加入Sm，提高了催化剂的活性和稳定性．对催化剂进行XRD和TPR表征结果表明M和Sm之间有强相互作用，Sm促进了Ni-MgO固溶体中Ni^2＋的还原．碳产物的TEM和TGA表征结果表明，在650℃得到的碳纳米管产率高（达到600％以上）、质量好．利用Ni-Sm-MgO催化剂上CO歧化制备碳纳米管是具有应用前景的大规模、低成本制备碳纳米管的方法．     

碳纳米管在水处理材料领域的应用*

碳纳米管是国内外广泛关注的一类碳材料,近年来逐渐成为水处理材料领域的一个研究热点。本文就碳纳米管在水处理材料领域应用研究进展作综合论述,介绍了基于碳纳米管水处理材料改性和制备方法,总结了碳纳米管用于水处理吸附材料、光催化降解复合材料、吸附材料载体以及湿式氧化催化剂载体等方面的研究进展,分析了碳纳米管作为吸附材料、吸附材料/催化材料载体以及碳纳米管用于光催化降解复合材料的原理。     

稀土催化材料研究与应用

稀土具有特殊的物理和化学性质,在化学反应过程中表现出良好的催化效果,在多种领域得到了广泛应用.目前,稀土催化材料在石油化工催化、机动车尾气催化、燃料电池催化、催化燃烧、制氢催化及其他环保催化的相关材料方面发挥着重要的作用.尽管稀土催化应用广泛,但是稀土对于各个催化过程的作用鲜见系统总结,因此,本文主要对近年来上述领域关...     

低温催化裂解烷烃法制备碳纳米管

低温催化裂解烷烃法制备碳纳米管陈萍，王培峰，林国栋，张鸿斌，蔡启瑞（厦门大学化学系固体表面物理化学国家重点实验室，厦门，３６１００５）关键词碳纳米管，催化裂解，甲烷碳纳米管的制备与研究是国际上新材料领域的探索热点［１］．由于具有纳米级的管径，碳纳米管...     

单壁碳纳米管自还原法制备负载Pt催化剂及其催化性能

金属Pt是良好的催化加氢、脱氢催化剂, 利用单壁碳纳米管(SWNTs)自身的还原性, 将K2PtCl6溶液中的Pt直接还原并负载在SWNTs表面上, 制备了具有良好催化性能的SWNTs/Pt负载型催化剂. 通过TEM, XPS和TG对材料进行了表征, 研究了K2PtCl6浓度及溶剂对Pt负载量、粒径的影响, 并测试了SWNTs/Pt的催化性能. 实验结果表明, SWNTs负载的Pt颗粒小, 分散均匀, 负载量高, 与SWNTs结合紧密, 催化性能好, 是催化加氢和脱氢反应的良好催化剂.     

n型金刚石薄膜催化生长碳纳米管

研究了n型金刚石薄膜作为催化剂生长碳纳米管的方法.首先采用丙酮裂解化学气相沉积(CVD)法制备均匀的n型金刚石薄膜,然后采用乙醇为碳源的CVD法,在850、900和950℃下,分别在n型金刚石薄膜上制备了碳球、竹节状碳管和多壁碳纳米管.所得产物用扫描电子显微镜、透射电子显微镜、拉曼光谱和X射线光电子能谱表征.实验结果表明产物的形貌与反应温度有关.我们还提出了与金刚石催化生长碳纳米管结果相符的实验机理.     

碳纳米管催化氧化脱氢反应的研究进展

碳纳米管(CNTs)具有比表面积大、热稳定性高、电子传递性好及吸附能力强等独特的性质,近年来其作为催化剂应用于催化氧化脱氢(ODH)反应受到广泛关注。作为ODH反应的非金属催化剂,CNTs具有催化效率高、选择性好、稳定性强及污染小和可重复利用等优点。本文综述了由CNTs催化的ODH反应类型、催化机理及影响因素,以期为今后CNTs作为催化剂更好地应用于ODH反应奠定理论和实验基础,同时也为进一步发掘CNTs作为其他反应的催化剂提供借鉴。     

功能化多孔材料的制备及其在特异性识别分离中的应用

功能化多孔材料(FPMs)具有优良的结构可控性、极大的比表面积、独特的空间互联孔结构,是一类理想的特异性识别、分离材料。本文系统介绍了FPMs的制备方法及其在特异性识别、分离中的应用。首先,对FPMs制备的基本理论和前沿设计理念进行阐述;继而深入剖析了FPMs的制备原理和合成过程中的关键因素,综述了FPMs在特异性识别和提取天然物功能成分、分离去除污染物以及催化反应等方面的作用机理及相关应用,分析和展望了FPMs在特异性识别、催化、分离等领域应用中存在的问题和发展趋势。     

Synthesis of carbon nanotubes by catalytic pyrolysis method with Feitknecht compound as precursor of NiZnAl catalyst

Carbon nanotubes are synthesized by catalytic pyrolysis method with a kind of new type catalyst--nickel-zinc-alumina catalyst prepared from Feitknecht compound. Tubular carbon nanotubes, bamboo-shaped carbon naotubes, herringbone carbon nanotubues and branched carbon nanotubes are all found formed at moderate temperature. It is important for the formation of quasi-liquid state of the metal nanoparticles at the tip of carbon naotubes during the growth of carbon nanotubes to lead to different kinds of carbon nanotubes. It is likely that the addition of zinc make the activity of nickel catalyst after calcinations and reduction changed strangely.     

CVD synthesis of spiral carbon nanotubes over asymmetric catalytic particles

The influence of asymmetric catalytic particles prepared by various methods was investigated on the growth of spiral carbon nanotubes using the CVD method. Asymmetric particles were prepared by either milling or crystallization from oversaturated solution onto the surface of catalyst support or catalyst impregnation at pH 8–9. As-prepared catalysts were tested in the decomposition of acetylene. Carbon deposit, thus carbon nanotubes and spirals were observed by transmission electron microscopy the activity was characterized by carbon yield.     

Three-dimensional bundle-like multiwalled carbon nanotubes composite for supercapacitor electrode application

Bundle-type mutil-walled carbon nanotubes (MWCNTs) composite electrode is the first investigation and publication for the supercapacitor application. According to the thermogravimetric analysis results, as-synthesized BCNTs are considered as the electrode materials for supercapacitors and electrochemical double-layer capacitor in this study. The Brunauer–Emmett–Teller specific surface area of as-prepared bundled carbon nanotubes (BCNTs) is 95.29 m²/g given to a type III isotherm and H3 hysteresis loops. Slow scanning rates promote and enhance to achieve high C_b because of the superior conductivity of CNT bundles and one side close-layered Ni/Mg/Mo alloy inside the BCNT-based electrode and facile electron diffusivity between electrolyte and electrode. The specific capacitance C_s (1,560 F/g) is nearly equal to the maximum specific capacitance, which the BCNT-based composite electrode can actually be able to charge or fill in. The maximum energy density value is 195 Wh/kg with corresponding power density values of 0.21 kW/kg. Furthermore, the active 3D BCNTs material fabricated electrode enhances to contact the electrolyte directly and decreases the ion diffusion limitation. Electrochemical impedance spectroscopy spectrum summarized as the low-frequency area controls by mass transfer limitation, and the high-frequency area dominates by charge transfer of kinetic control. After 2,000 consecutive cyclic voltammetry sacnings and galvanostatic charge-discharge cycles at a current density of 1.67 A/g performs, the specific capacitance retentions of 3D BCNTs electrodes achieved 128.2 and 77.3%, respectively. Three-dimensional BCNT composite electrodes exhibit good conductivity and low charge transfer resistance, which is beneficial to fast charge transfer between the BCNTs electrode materials and electrolytes.     

Catalytic synthesis of carbon nanotubes from ethylene in the presence of water vapor

Multiwalled carbon nanotubes were synthesized catalytically from ethylene in the presence of water vapor at transition metals of the iron subgroup. The structure of the obtained nanotubes was studied by transmission electron microscopy, high-resolution transmission electron microscopy, and Raman spectroscopy. It was shown that the highest yields of carbon nanotubes with diameters between 20 and 40 nm, lengths of more than 1 μm, and average diameter of 0.92 nm for the innermost tube were obtained at a nickel catalyst with a water vapor concentration of 0.32%. __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 42, No. 4, pp. 227–230, July–August, 2006.     

Ionic liquids for soft functional materials with carbon nanotubes

A serendipitous finding that ionic liquids gel with carbon nanotubes has opened a new possibility of ionic liquids as modifiers for carbon nanotubes. Upon being ground into ionic liquids, carbon nanotube bundles are untangled, and the resultant fine bundles form a network structure. This is due to the possible specific interaction between the imidazolium ion component and the pi-electronic nanotube surface. The resultant gelatinous materials, consisting of highly electroconductive nanowires and fluid electrolytes, can be utilized for a wide variety of electrochemical applications, such as sensors, capacitors, and actuators. Ionic liquids allow for noncovalent and covalent modifications of carbon nanotubes and fabrication of polymer composites with enhanced physical properties. The processing of carbon nanotubes with ionic liquids is not accompanied by the disruption of the pi-conjugated nanotube structure and does not require solvents; therefore it can readily be scaled up. This article focuses on new aspects of ionic liquids for designer soft materials based on carbon nanotubes.     

多壁碳纳米管修饰电极上阿替洛尔电化学行为的研究及其测定

基于多壁碳纳米管修饰玻碳电极对阿替洛尔的催化作用,建立了测定阿替洛尔的电化学分析方法。多壁碳纳米管修饰玻碳电极与裸玻碳电极相比,显著提高了阿替洛尔的氧化峰电流,降低了氧化峰电位,提高了测定的灵敏度。该电极测定阿替洛尔的线性范围为4.9×10-6~6.3×10-4mol/L,检出限为2×10-6mol/L。对1.3×10-4mol/L阿替洛尔进行11次平行测定,相对标准偏差为4.4%。此法可用于阿替洛尔片剂中阿替洛尔的测定。     

Synthesis and characterization of nickel catalysts supported on different carbon materials

Nickel catalysts supported on various carbon materials such as multiwall carbon nanotubes, shortened length carbon nanotubes, graphite and amorphous carbon were synthesized, characterized and tested in cyclohexene hydrogenation reaction. We have found that carbon nanotube supports are superior to graphite and amorphous carbon both in terms of catalytic activity and stability.     

碳纳米管在样品前处理中的应用

碳纳米管是一维碳基纳米材料,具有独特的管状结构、良好的化学稳定性、热稳定性和高比表面积.近年来,碳纳米管在有机小分子、金属离子和生物大分子分离富集方面得到了广泛的应用.本文综述了碳纳米管及功能化碳纳米管在固相萃取、固相微萃取、中空纤维膜保护固相微萃取和液膜萃取等样品前处理技术中的应用.     

过渡金属氧化物和金属负载型沸石催化剂上合成 纳米碳管及其表征

采用气相催化沉积法催化合成纳米碳管,比较了不同金属氧化物和金属负载型沸石催化剂以及不同分子筛载体对合成纳米碳管的影响,并用TEM,XRD表征其形貌和结晶度,用DTA-TG考察了纳米碳管的热和稳定性。实验结果表明纳米碳管的形成除了与金属种类有关外,还直接与催化剂的颗粒大小和分散状态有关。粒径在20nm左右的不规则形状的纳米粒子是形成纳米碳管的活性组分,非负载和负载型的催化剂均表明活性组分的粒径与纳米碳管的管径有一定的对应关系。化学提纯后能得到高纯度的纳米碳管;其管壁具有较好的石墨化结构,在空气中的热稳定性大于400℃,而在氮气中能维持到1200℃以上。