国外动态

国外动态填充铂的碳钠米管日本东北大学的化学家ＴａｋａｓｈｉＫｙｏｔａｎｉ等已将铂成功地填充入碳纳米管。他们利用一模板制备具有均一长度、直径和壁厚的碳纳米管。使用的模板是带有一系列具有纳米级直径的平行孔道的氧化铝膜。用六氯铂酸的乙醇溶液浸渍此膜。六氯铂...     

多壁碳纳米管分散性研究

通过对多壁碳纳米管的改性研究,寻找提高碳纳米管分散性的途径。采用NaOH对碳纳米管进行预处理,通过SEM、DSC分析表明,该处理过程对去除多壁碳纳米管中杂质和提高其分散性有积极效果。通过H2SO4和HNO3的混酸处理法与HNO3处理法的对比,知前者对碳纳米管的损失要大于后者,且通过对FTIR的对比分析,后者对碳纳米管的改性效果好于前者。TG、TEM分析表明,聚乙烯醇均匀包覆在碳纳米管表面,碳纳米管分散性较酸处理的有所改进。     

不同碱和酸处理对碳纳米管结构和形貌的影响

研究了不同碱和酸处理对碳纳米管的微观结构和形貌的影响,采用TEM、SEM和XRD对其进行了表征。K_2CO_3、NaOH和KOH在750℃处理多壁碳纳米管时发现:NaOH的氧化刻蚀能力最强,K_2CO_3的氧化刻蚀能力最弱;强碱能够强烈地刻蚀碳纳米管的管壁,使碳纳米管的管壁变薄,变粗糙,并且有孔洞结构形成,同时造成内径扩大。硝酸处理碳纳米管时发现:随着处理时间的延长碳纳米管管壁变薄,内径变大,但是当处理时间超过16 h后,碳纳米管的管径变化不是很明显,但有大量的碳纳米管被短切。碱处理与酸处理对碳纳米管的微观结构和形貌的影响有很大差异,这是由于碱和酸对碳纳米管的氧化刻蚀的反应环境和刻蚀机理不同。     

金属铂-稀土合金电催化剂的制备研究

基于贵金属铂在甲醇燃料电池上的广泛应用,采用不同稀土金属(如钪、钇、镧系等)与铂形成合金在酸性条件下研究其对甲醇的电催化性能,并利用多壁碳纳米管增强对甲醇小分子的吸附性,提高酸性环境下甲醇的电催化氧化效率。多壁碳纳米管(MWNTs)具备纳米级别的管状结构,比表面积大,是一种优良载体,将铂-稀土合金和多壁碳纳米管充分混杂,并修饰在玻碳电极(GC)表面,具有良好的化学和物理稳定性。通过上述分析和实验制备了铂-稀土(M-Pt)合金催化剂、铂-稀土/多壁碳纳米管(M-Pt/MWNTs)催化剂。实验证明铂与稀土金属钪、钇、镧系等形成的合金的电催化性能最佳,且加入多壁碳纳米管,形成的铂-稀土/多壁碳纳米管(M-Pt/MWNTs)催化剂电化学催化效率得到明显地提升,所制备的铂-稀土合金电催化剂实用价值高。     

酸化多壁碳纳米管/水性聚氨酯复合材料的制备与性能研究

采用混酸对多壁碳纳米管进行表面处理,通过共混法制备出酸化多壁碳纳米管/水性聚氨酯(WPU)复合材料。通过FT-IR,拉曼光谱,SEM表征了多壁碳纳米管酸化前后的结构,通过TGA、拉力测试以及SEM研究了复合材料的热性能、力学性能和微观结构。结果显示,多壁碳纳米管通过混酸处理后表面羧基化,管壁卷曲程度降低。与纯WPU相比,当添加量为1.5%时,复合材料的断裂伸长率增加29%,当添加量在2%时,复合材料的拉伸强度增加169%,酸化碳纳米管在聚氨酯(PU)基体中均匀分散。酸化碳纳米管的添加显著提高了复合材料的热稳定性和导电性。     

染料敏化太阳能电池非铂对电极研究进展

对电极作为染料敏化太阳能电池（dye-sensitized solar cell,DSSC）的重要组成部分,对电极材料性能的好坏直接影响着染料敏化太阳能电池的光电转化效率。最常使用的对电极电催化材料是贵金属铂,而铂十分稀少而且价格昂贵,并且铂很容易被碘电解液腐蚀,不利于染料敏化太阳能电池的产业化发展。本文重点综述了2010年以来染料敏化太阳能电池非铂对电极的研究成果,简要说明了对电极在染料敏化太阳能电池中的作用,详细介绍了非铂金属、碳材料、导电聚合物和无机化合物等对电极材料,分析了各类非铂对电极材料的特点、制备工艺、发展前景、优缺点和改进措施。最后提出,继续开发各种成本低、原料易得以及稳定高效的新型非金属对电极材料仍是今后染料敏化太阳能电池研究的一个重要方向。     

多壁碳纳米管对电极染料敏化太阳能电池的制备及电化学性能

以钛酸丁酯为钛源,F：SnO2（FTO）为导电玻璃载体,通过溶胶–凝胶法制备TiO2光阳极;并用3种不同多壁碳纳米管（multi-walled carbon nanotubes,MWCNTs）制备对电极。利用X射线衍射仪和热重–差热分析对TiO2光阳极制备过程中晶体结构和热化学变化进行分析;采用扫描电子显微镜、红外光谱...     

钛基镀铂电极的应用

钛基镀铂电极系天津大学应化系钛基镀铂小组承接化工部委托的“六五”攻关项目。经过两年多的研究与应用试验,最终取得成果,于1986年11月27日通过部级鉴定。该电极以钛网、钛板作为基材,从水溶液中采用脉冲镀铂的方法而制成。电极性能稳定,使用寿命长。     

多壁碳纳米管改性航空轮胎橡胶材料的制备方法

正由中国民航大学申请的专利(公开号CN105482175A,公开日期2016-04-13)"多壁碳纳米管改性航空轮胎橡胶材料的制备方法",涉及的多壁碳纳米管改性航空轮胎橡胶材料的制备方法为:将多壁碳纳米管分散在阴离子表面活性剂水溶液中获得悬浮液,在悬浮液中加入天然胶乳,经过共混乳液的絮凝共沉和过滤干燥,得到由多壁     

活性炭修饰微生物燃料电池阳极的研究

利用活性炭修饰碳布作为微生物燃料电池阳极,并与多壁碳纳米管修饰的阳极和未修饰的碳布进行了的比较。结果表明,装配活性炭修饰碳布阳极运行的微生物燃料电池获得的最大功率密度为510 mW/m2,相较于多壁碳纳米管修饰的阳极和未修饰的碳布阳极分别提升了7%和54.5%。电极的电化学性质利用循环伏安法(CV)和交流阻抗谱(EIS)测试表明,活性炭修饰碳布具有良好的电化学特性。     

酸化处理对碳纳米管改性聚氨酯性能的影响

近年来,碳纳米管以其优异的性能引起了极大的关注,从而广泛用于改性聚合物材料。采用浓硫酸和浓硝酸的混合酸对多壁碳纳米管进行酸化处理,并采用原位聚合法制备了碳纳米管改性聚氨酯材料,研究了碳纳米管的酸化处理对材料力学性能和热稳定性的影响。结果表明,碳纳米管的加入使得聚氨酯材料的拉伸强度和弹性模量升高,断裂伸长率减小,提高了聚氨酯材料的热稳定性,而且经过酸化的碳纳米管对聚氨酯材料的改性要比未酸化碳纳米管对聚氨酯材料的改性效果更为显著。     

Mass production of high-quality multi-walled carbon nanotube bundles on a Ni/Mo/MgO catalyst

A new catalyst (Ni/Mo/MgO) is reported, with which one can synthesize multi-walled carbon nanotube (MWNT) bundles with a yield of more than 45 times the amount of the pristine catalyst, using a methane-hydrogen mixture as precursor. Powder X-ray diffraction, Raman spectroscopy and thermal gravimetric analysis show that the purity of the as-prepared MWNTs is over 97%. The diameter of the carbon nanotubes is 9-20 nm, measured by high-resolution electron microscopy on 421 individual MWNTs. The high purity of the as-prepared MWNTs allows us to omit the usual complex purification process required for carbon nanotubes synthesized by chemical vapor deposition. Because of its durable high activity, the Ni/Mo/MgO catalyst in its pristine state is ideal for mass production of high-quality MWNTs. The synergism of nickel and molybdenum is considered the main reason for the high yield of carbon nanotubes.     

Preparation and characterization of alkylated carbon nanotube/polyimide nanocomposites

BACKGROUND: The development of carbon nanotube‐reinforced composites has been impeded by the difficult dispersion of the nanotubes in polymers and the weak interaction between the nanofiller and matrices. Efficient dispersion of carbon nanotubes is essential for the formation of a functional nanotube network in a composite matrix. RESULTS: Multiwalled carbon nanotubes (MWNTs) were incorporated into a polyimide matrix to produce MWNT/polyimide nanocomposites. To disperse well the MWNTs in the matrix and thus improve the interfacial adhesion between the nanotubes and the polymer, ‘branches’ were grafted onto the surface of the nanotubes by reacting octadecyl isocyanate with carboxylated MWNTs. The functionalized MWNTs were suspended in a precursor solution, and the dispersion was cast, followed by drying and imidization to obtain MWNT/polyimide nanocomposites. CONCLUSION: The functionalized MWNTs appear as a homogeneous dispersion in the polymer matrix. The thermal stability and the mechanical properties are greatly improved, which is attributed to the strong interactions between the functionalized MWNTs and the polyimide matrix. Copyright © 2009 Society of Chemical Industry     

Modification of multi-walled carbon nanotubes with fatty acid and their tribological properties as lubricant additive

Multi-walled carbon nanotubes (MWNTs) were treated with mixture of sulfuric acid and nitric acid. The surface modification of the oxidized MWNTs was achieved by refluxing the MWNTs with stearic acid (SA). The modified MWNTs were examined by the transmission electron microscope, scanning electron microscope, Raman spectroscopy and Infrared spectroscopy. Furthermore, the modified MWNTs were added to base lubricant and the tribological properties of resultant MWNTs lubricant were investigated by using a pin-on-plate wear tester. The results indicated that an esterification was formed in the oxidized MWNTs and SA, and the modification led to an improvement in the dispersion of MWNTs and the tribological properties of MWNTs as lubricant additive.     

Photocatalytic degradation of alizarin red dye in aqueous medium using carbon nanotubes/Cu–Ti oxide composites

ABSTRACT

Multiwalled carbon nanotubes/copper and titanium oxides (MWNTs/Cu–Ti) and Cu–Ti composites were synthesized by wet chemical precipitation method and were used as photocatalysts for photodegradation of alizarin red dye in aqueous media. The morphological study presented that MWNTs are well covered by Cu–Ti. The formation of Cu–Ti was confirmed by energy dispersive X-rays (EDX) and X-rays diffraction (XRD). The MWNTs/Cu–Ti degraded about 92.51% within 180 min. The effect of other parameters like pH, catalyst dosage, and concentration of dye on the photocatalytic degradation was also studied. The activity of recovered and re-recovered catalysts was also studied.     

Preparation of short carbon nanotubes by mechanical ball milling and their hydrogen adsorption behavior

Short multi-wall carbon nanotubes (MWNTs) with open tips were obtained by mechanical ball milling. The microstructure characteristics of MWNTs before and after ball milling were checked by transmission electron microscopy (TEM). The effect of ball milling on the hydrogen adsorption behavior of the MWNTs was studied. The hydrogen adsorption experiments were carried out at room temperature under a pressure of 8-9 MPa. The hydrogen adsorption capacity of carbon nanotubes milled for 10 h was 0.66 wt%, which was about six times that of MWNTs without milling. For the carbon nanotubes milled with MgO for 1 h, a hydrogen adsorption capacity of 0.69 wt% was obtained. The enhancement of hydrogen adsorption might result from the increase of defects and surface area of the MWNTs caused by ball milling.     

Amino‐functionalized multiple‐walled carbon nanotubes‐polyimide nanocomposite films fabricated by in situ polymerization

For the preparation of high‐quality polymeric carbon nanocomposites, it is required that carbon nanotubes are fully compatible with matrix polymers. For this purpose, amino‐functionalized multiple‐walled carbon nanotubes (a‐MWNTs) were synthesized. The a‐MWNTs/polyimide nanocomposite films were prepared through in situ polymerization. According to the spectroscopic characterizations, the a‐MWNTs were homogeneously dispersed in the nanocomposite films as the acid‐functionalized MWNTs. The mechanical properties of the polyimide composite were also studied. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Ultrasound assisted twin screw extrusion of polymer-nanocomposites containing carbon nanotubes

The unique morphology and strong intertube attraction between carbon nanotubes (CNTs) make the dispersion of CNTs challenging and hence limit its effective use. A novel method for the continuous dispersion of multi-walled carbon nanotubes (MWNTs) in a polymer matrix for manufacturing high performance nanocomposites was developed using an ultrasonically assisted twin screw extrusion process. Reduction of the die pressure and variation of the ultrasonic power consumption as a function of amplitude were measured at various MWNT loadings. The effect of ultrasound on rheological, electrical, morphological and mechanical properties of polyetherimide (PEI) matrix and PEI-filled with 1-10 wt% MWNTs was studied. In the treated nanocomposites, the complex viscosity, storage and loss moduli were increased and damping characteristics were decreased as compared to untreated ones. Rheological and electrical percolations were found to be between 1 and 2 wt% MWNT loading. Ultrasonic treatment does not affect the electrical conductivity of nanocomposites. Mechanical properties such as Young's modulus and tensile strength were significantly increased with MWNT loading but moderately with ultrasonic treatment at high loadings and certain ultrasonic amplitudes. The morphology and state of dispersion of MWNTs were investigated by means of HRSEM. In the ultrasonically treated nanocomposites, the obtained micrographs showed excellent dispersion of MWNTs in PEI matrix.     

Multiwalled carbon nantoubes‐reinforced poly(hydroxyaminoether) prepared by one pot graft‐from method

Multiwalled carbon nanotubes (MWNTs)‐reinforced poly(hydroxyaminoether) (PHAE) was fabricated via one pot graft‐from method. The modification of MWNTs and in situ polymerization of PHAE were combined in one reaction pot without interruption for the purification of modified carbon nanotubes. Fourier transform infrared, scanning electron microscopy, transmission electron microscopy, and Raman spectra clearly indicated that PHAE was successfully attached to the surface of MWNTs via esterification reaction between epoxy and carboxylic acid from MWNTs. Tensile tests showed that the tensile strength and modulus of PHAE/MWNTs composites were improved compared with that of pristine PHAE. Moreover, the reinforcing effect of one pot graft‐from method was found to be better than that of graft‐to method. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011