溶胶-凝胶法制备油脂加氢催化剂的研究

采用溶胶－凝胶法，制备了可用于食用油脂加氢的单元镍催化剂，研究了催化剂制备方法对催化剂镍含量的影响及镍含量的变化对活性的影响。研究表明：镍含量最佳值在20％左右，催化剂的活性随镍含量增加而提高，采用乙醇代替水洗可有效提高催化剂的镍含量和催化活性。     

反应时间对VCD法制备多壁碳纳米管产率和形貌的影响

以甲烷为碳源气，以氢气为载气和还原气，以自制纳米NiO/SiO2气凝胶为催化剂，探讨了气相化学沉积法制备碳纳米管工艺过程中，反应时间对产物产率和形貌的影响。实验结果表明，随反应时间的延长，碳纳米管的产率不断提高，一定时间后增长趋于平缓，TEM图象表明碳纳米管的长径比也随之增加。     

载镍碳纳米管的载镍量分析

采用灼烧法预处理、丁二酮肟重量分析法来测定载镍碳纳米管的载镍量,获得稳定而准确的分析结果。结果表明,制备载镍碳纳米管催化剂时所加入的镍并不全部吸附在碳纳米管上;载镍效率随着碳纳米管载镍量的增加而降低。     

新型镍基镁渣催化重整松木热解挥发分焦油析出特性研究

采用过量浸渍法制备了镍基镁渣催化剂，并在小型气流床气化炉上开展了松木热解挥发分的催化重整研究。评估了煅烧/催化温度、镍含量和水碳比对焦油组分的影响，同时在不同煅烧/催化温度下与Ni/γ-Al₂O₃催化剂进行了裂解焦油性能的对比。采用比表面积测试（BET）、X射线衍射（XRD）、扫描电镜（SEM）和透射电镜（TEM）对催化剂进行了表征。结果表明，当镍含量为3%，煅烧/催化温度为800℃，水碳比为0.5时，镍基镁渣催化剂表现出最优异的催化裂解焦油能力：大幅度降低了重质多环芳烃的相对含量，并且焦油转化率达到95.69%，同时焦油露点温度降至40.2℃。XRD结果表明，Ni、Fe、Ca、Mg相互作用可以形成多种活性中心，进而协同提高催化剂活性。     

高性能PtNi合金催化剂构筑及其对甲醇电催化

以多壁碳纳米管（CNTs）为载体，H2PtCl6·6H2O为铂源、Ni(NO3)2·6H2O为镍源，硼氢化钠和乙二醇为还原剂，采用一锅法制备了一种PtNi/CNTs合金电催化剂。采用XRD、SEM、TEM、HR-TEM、XPS、ICP-OES和Raman对催化剂结构进行表征。采用循环伏安法（CV）、计时安培法（i-t）和CO溶出曲线法评价了催化剂的电化学活性与稳定性。结果表明，PtNi/CNTs对甲醇电催化氧化（MOR）反应具有优异的电催化性能，峰值电流和稳态电流分别是商业Pt/C的5.89倍和38.97倍，同时，PtNi/CNTs还表现出良好的稳定性，主要归因于碳纳米管独特的结构与双金属合金的协同效应。     

Co／Mo催化剂制备碳纳米管的研究

以氧化铝凝胶负载Co／Mo合金为催化剂，C2H2为碳源，用CVD法合成了纯度较商的多壁碳纳米管（MWCNT）。通过甩TEM和XRD等方法，对碳纳米管（CNTs）进行了表征，表明制备的碳纳米管具有较高的石墨化程度。研究得出当催化剂的沉淀pH=7．5，H2为还原气和载气，升温速率为50℃／min时，碳纳米管的纯化后的产率高达85％，为下一步的大规模化生产打下了良好构基础。     

氢气流量和反应时间对焦化苯裂解制备碳纳米管的影响

以工业级焦化苯为碳源,以二茂铁为催化剂前躯体,以噻吩为生长促进剂,采用催化裂解(CVD)法制备碳纳米管,通过TEM进行形貌表征,着重探讨氢气流量和反应时间对碳纳米管形貌和产率的影响。结果分析表明:氢气流量和反应时间在一定范围内增加时,所得碳纳米管的管壁直,缺陷少,纯度高,且纯化后产率增加。因此,通过控制氢气流量和反应时间可以控制碳纳米管的形貌,而且能够提高碳纳米管的产率。     

过渡金属修饰的碳纳米管降低烟气中氢氰酸

分别制备了高产率的修饰铁、钴、镍的碳纳米管,将铁、钴、镍修饰的碳纳米管添加到卷烟嘴棒中可提高烟气中有害成分氢氰酸的吸附效果。实验结果表明：添加了修饰铁、钻、镍的碳纳米管的卷烟嘴棒,可明显选择性降低烟气中有害成分氢氰酸的含量,其中铁修饰碳纳米管降低氢氰酸和焦油的效果最好,随着铁修饰碳纳米管的添加量增加,烟气中氢氰酸和焦油的量减少,烟气中氢氰酸的含量减少16．8％-32％,焦油的含量降低9．8％～26％。     

反应时间对CVD法制备多壁碳纳米管产率和形貌的影响

以甲烷为碳源气,以氢气为载气和还原气,以自制纳米NiO/SiO2气凝胶为催化剂,探讨了气相化学沉积法制备碳纳米管工艺过程中,反应时间对产物产率和形貌的影响.实验结果表明,随反应时间的延长,碳纳米管的产率不断提高,一定时间后增长趋于平缓,TEM图象表明碳纳米管的长径比也随之增加.     

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。     

Optimization of plasma-enhanced chemical vapor deposition parameters for the growth of individual vertical carbon nanotubes as field emitters

In this article plasma enhanced growth of single vertical carbon nanotubes (CNTs) from individual nickel catalyst dots is studied, aiming at the fabrication of CNT field emitters. It is found that the growth of individual CNTs differs from that of CNT forests grown from unpatterned catalyst films, an effect that can be attributed to the difference in catalyst volumes. In the context of growth parameters the influence of temperature, growth time, catalyst volume, pressure and power is characterized. After determining the growth behavior, an individual CNT of desired geometry is fabricated on a conducting lead. The CNT is electrically characterized in terms of its field emission behavior and stable emission currents and its work function is determined to Φ = 5.4 ± 0.2 eV.     

煤基聚苯胺制掺N碳微纳米管的实验研究

我国煤炭资源丰富,以煤为原料制备碳纳米管,可以实现煤炭资源的高效利用,减少环境污染,为煤炭行业的发展提供新途径。以煤基聚苯胺为碳氮源,分别以乙酸镍或柠檬酸铁为碳源热解催化剂,以二茂镍、乙酸镍或二茂铁为碳管生长催化剂,采用催化热解-化学气相沉积耦合法成功制备出了三种高石墨化程度的掺N碳微纳米管。并对其进行了SEM、TEM、XRD、Raman、XPS等结构测试和甲醇氧化电催化剂载体应用测试,结果发现：三种掺N碳微纳米管的微观形态多样,有直立管、弯曲管、竹节状管等。二茂镍和二茂铁适合生长长而直的碳管,乙酸镍适合生长短而弯的碳管。二茂镍和乙酸镍所长碳管收率相当,约为5.8%（质量）;二茂铁所长碳管收率较高,为21.2%（质量）。N元素主要以石墨型N掺入三种碳微纳米管中,乙酸镍所长碳管的掺N量最高,为1.17%（质量）,且表现出良好的电催化剂载体性能。     

碳纳米管负载壳聚糖络合铂配合物的制备及其催化硅氢加成性能

将壳聚糖(CS)负载到碳纳米管(CNT)上得到CNT-CS,再与Pt配位,制得CNT负载CS络合铂配合物(CNT-CS-Pt).将后者用作烯丙基缩水甘油醚和三乙氧基硅烷的硅氢加成反应的催化剂,并考察了该配合物的催化性能.结果表明,Pt与CS中的N原子配位形成Pt-N配位键;该催化剂在烯丙基缩水甘油醚和三乙氧基硅烷的反应中表现出极好的区域选择性及良好的催化活性,β-加成产物的选择性为100%,130 ℃下反应180 min,产物的收率达到70.4%.该催化剂可通过简单的方法回收但重复使用性能有一定下降,重复使用4次后产物的收率下降到24.0%.并对催化机理进行了初步的探讨.     

The effect of sulfur on the number of layers in a carbon nanotube

This study shows that S concentration in the Fe catalyst plays an important role in controlling the number of graphene layers during carbon nanotube (CNT) growth via chemical vapor deposition. Using different S concentrations, we have grown thin carbon nanotubes with from 1 to 5 layers. Single-walled carbon nanotubes growing from the active surface of an FeS-Fe eutectic were observed. A growth model basing on the HRTEM characterization and thermodynamic analysis is suggested in which the CNT nucleates and grows on the active surface area of the catalyst where S accumulates in the form of an FeS-Fe eutectic, and the S distribution on the catalyst particle surface determines the number of CNT layers.     

Synthesis and electro-catalytic activity of methanol oxidation on nitrogen containing carbon nanotubes supported Pt electrodes

Template synthesis of various nitrogen containing carbon nanotubes using different nitrogen containing polymers and the variation of nitrogen content in carbon nanotube (CNT) on the behaviour of supported Pt electrodes in the anodic oxidation of methanol in direct methanol fuel cells was investigated. Characterizations of the as-prepared catalysts are investigated by electron microscopy and electrochemical analysis. The catalyst with N-containing CNT as a support exhibits a higher catalytic activity than that carbon supported platinum electrode and CNT supported electrodes. The N-containing CNT supported electrodes with 10.5% nitrogen content show a higher catalytic activity compared to other N-CNT supported electrodes. This could be due to the existence of additional active sites on the surface of the N-containing CNT supported electrodes, which favours better dispersion of Pt particles. Also, the strong metal-support interaction plays a major role in enhancing the catalytic activity for methanol oxidation.     

Observations of novel carbon nanotubes with multiple hollow cores

Usually carbon nanotubes (CNTs) containing only one hollow core are obtained from the catalytic decomposition of hydrocarbons when hydrocarbon gases flow straight into the reaction tube. However, unusual carbon nanotubes with multiple hollow cores were observed when the gas-feed method was changed in an attempt to increase CNT production yield using a floating catalyst method. The fraction of multicored carbon nanotubes can be as high as 60%. The formation of such an unusual structure is ascribed to the introduction of pentagon and heptagon defects to the CNTs in the growth process, owing to the change of gas-feed method. This finding enriches the family of CNTs and could be helpful in understanding the CNT formation mechanism.     

Plasma-thermal purification and annealing of carbon nanotubes

We have developed a very fast and entirely gas-phase based purification technique for carbon nanotubes (CNT) that allows removing metal and metal oxide impurities with high effectiveness. CNT agglomerates from chemical vapor deposition (CVD) synthesis which contained carbon encapsulated catalysts were injected into an atmospheric plasma torch. Very high heating rates allow for quasi-instantaneous vaporization of catalyst particles. This way, metal vapors are hyposized to break mechanically instable encapsulations and effuse from incomplete ones faster than thermally induced graphitization stabilizes such particle encapsulations. The ash content of multi-walled (MW) CNT samples was reduced to less than 15% of the initial value within a few milliseconds. Also the metal content of single-walled (SW) CNT agglomerates was significantly reduced. Repeated injection of CNT agglomerates into the plasma torch resulted in higher-purity products of improved structural integrity and increased oxidation resistance.     

A plasma enhanced chemical vapor deposition process to achieve branched carbon nanotubes

Vertically aligned carbon nanotubes (CNTs) have been grown on silicon substrates using nickel as the catalyst layer, acetylene as the carbon source, and hydrogen as the carrier gas. The quality of the CNTs has been examined using transmission and scanning electron microscopy and a tip-growth mechanism with an inner tube diameter of 5–8 nm was observed. The effect of plasma hydrogenation as a post-growth treatment was shown to lead to total or partial removal of the nickel seeds from the CNT tips. Using sequential hydrogenation and growth, it has been possible to achieve tree-like nanostructures.     

Nano carbon hybrids from the simultaneous synthesis of CNT/NCD by MPCVD

A carbon hybrid composed by nanocrystalline diamond (NCD) and carbon nanotubes (CNT) was successfully synthesized by microwave plasma chemical vapor deposition (MPCVD), assisted by a continuous delivery of a Fe catalyst. This way, both carbon forms were grown simultaneously, originating a composite structure mainly formed by nanodiamond conglomerates well interconnected by multiwall carbon nanotubes. NCD clusters often develop at the crossing points of different CNTs. A good NCD/CNT mechanical link is predicted based on the observation of carbon nanotubes penetrating and/or involving isolated nanocrystalline diamond clusters. The overall appearance of the NCD/CNT material resembles that of a 2D neuronal network. The nanocrystalline diamond and carbon nanotube phases were structurally confirmed by μ-Raman spectroscopy, the morphological features were characterized by SEM and EDS was used to appraise the catalyst surface distribution.     

Controllable‐Nitrogen Doped Carbon Layer Surrounding Carbon Nanotubes as Novel Carbon Support for Oxygen Reduction Reaction

Novel nitrogen‐doped carbon layer surrounding carbon nanotubes composite (NC‐CNT) (N/C ratio 3.3–14.3 wt.%) as catalyst support has been prepared using aniline as a dispersant to carbon nanotubes (CNTs) and as a source for both carbon and nitrogen coated on the surface of the CNTs, where the amount of doped nitrogen is controllable. The NC‐CNT so obtained were characterized with scanning electron microscopy (SEM), Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS), and nitrogen adsorption and desorption isotherms. A uniform dispersion of Pt nanoparticles (ca. 1.5–2.0 nm) was then anchored on the surface of NC‐CNT by using aromatic amine as a stabilizer. For these Pt/NC‐CNTs, cyclic voltammogram measurements show a high electrochemical activity surface area (up to 103.7 m² g^–1) compared to the commercial E‐TEK catalyst (55.3 m² g^–1). In single cell test, Pt/NC‐CNT catalyst has greatly enhanced catalytic activity toward the oxygen reduction reaction, resulting in an enhancement of ca. 37% in mass activity compared with that of E‐TEK.