纳米催化技术的应用进展

概述了纳米微粒的制备技术;介绍了纳米催化技术,包括碳纳米管催化、纳米金属(簇)催化、纳米金属氧化物催化、纳米沸石组装与催化以及金属配合物/分子筛复合催化材料催化、纳米粒子/聚合物复合材料催化、无机/有机纳米复合膜材料催化等;对未来纳米催化技术发展提出建议:改进现有的制备方法,探索开发纳米材料制备新技术,研究纳米材料的评价与表征方法,深入开展基础理论研究,以及扩大各研究院校与产业部门间的科技合作。     

金属和半导体纳米微粒薄膜的制备

由于金属、半导体纳米微粒在光物理、光化学、光催化等方面具有突出的性能,因此如何将金属、半导体纳米微粒通过某些方式构建成某些薄膜材料,对实现纳米微粒在分子器件和光电器件方面的应用具有重要的意义。本文以制备方法为主线,介绍了几种构建金属、半导体纳米微粒薄膜的基本方法,对其中一些重要的问题进行了比较详细的讨论。     

非晶纳米复合镀层的摩擦学性能

对纳米陶瓷微粒及自润滑纳米粉改性的非晶纳米复合镀层的摩擦学性能进行了综述.分析了纳米陶瓷微粒ZrO2、SiC、Al2O3及具有自润滑性能的纳米MoS2、PTFE、碳纳米管(CNTs)改性的复合镀层的摩擦学行为,发现具有自润滑性能的复合镀层具有较好的摩擦学性能.     

一种碳纳米管内沉积金属粒子催化剂及其制备和应用

<正>申请号:CN201910799065.X申请日:20190827公开(公告)号:CN110624582A本发明公开了一种碳纳米管内沉积金属粒子催化剂,该催化剂由碳纳米管、碳量子点和金属纳米粒子组成;所述的碳纳米管为开孔的单壁或多壁碳管,碳纳米管外壁负载有碳量子点,碳纳米管内壁镶嵌有金属纳米粒子。本发明所述的制备方法是先将碳量子点负载到碳纳米管外壁,再利用碳量子点的给电子特性诱导带负电的金属络合离子自发进     

碳纳米管与金属纳米导线成功连接——可广泛用于计算机芯片、传感器等电子设备

美国罗斯塞拉(Rensselaer)工学院研究人员表示,他们找到了一种能将碳纳米管和金属导线相连接的新工艺,并用它研制出结合了碳纳米管和金属纳米导线最佳特性的纳米导线。新工艺有望帮助人们克服碳纳米管在计算机芯片、传感器和许多其他电子设备应用方面存在的主要障碍。此研究成果报告刊载在最新出版的《应用物理快报》上。为了获得碳纳米管和金属纳米导线的混合结构纳米导线,研究人员利用了氧化铝模板,模板中含有直径为纳米级尺寸的通道。他们先将分离的金属铜纳米导线(即两根导线间有缝隙)放入通道内,然后将整个装置放置在含富碳化合物的炉…     

金属纳米粒子修饰的碳纳米管研究进展

多壁和单壁碳纳米管（CNT）是被广泛研究的纳米材料之一,可以用作良好的金属或其它纳米粒子的载体。金属纳米粒子-碳纳米管复合材料在催化、传感、贮氢、及各种光学电学方面有广泛的应用前景,文章就近期各种碳纳米管负载的金属纳米材料（主要集中在贵金属）的合成做一小结。     

表面修饰Ag2S纳米微粒的合成与光谱表征

采用同阳离子共沉淀法制备了以硬脂酸和DDP为修饰剂的表面修饰Ag2S纳米微粒。通过调节金属硫化物与表面修饰剂浓度之比,采用不同的反应方式及滴加方式,找到了制备修饰Ag2S纳米微粒的适宜条件。并对其进行了光谱表征,其紫外吸收光谱表明所制备的修饰AgeS纳米微粒具有显著的量子尺寸效应。荧光光谱显示为表面态发光。     

超声波-电沉积Ni-Al_2O_3复合镀层的表面形貌及组织结构

采用超声波-电沉积方法在金属基体上制备纳米Ni-Al2O3复合镀层。研究了超声波频率、功率对制备复合镀层的影响。利用X射线衍射仪（XRD）、扫描电子显微镜（SEM）对镀层微观组织、表面形貌进行观察和分析。结果表明：超声波的作用可有效解决纳米Al2O3微粒在镀液中的分散问题,使纳米Al2O3微粒均匀分布在复合镀层中,促进纳米Al2O3微粒与镀层基质金属的共沉积,并细化基质金属Ni的晶粒,获得了由镍晶（20~40 nm）和纳米Al2O3微粒构成的纳米复合镀层。     

纳米微粒阻燃聚合物的研究进展

简要介绍了纳米微米阻燃聚合物的发展概况;综述了层状硅酸盐、碳纳米管、多面体低聚倍半硅氧烷、富勒烯及石墨烯等阻燃聚合物的研究现状及其应用,并对纳米微粒阻燃聚合物的发展前景进行了展望。     

日本可乐丽开发新型导电性纤维

<正>日本可乐丽公司采用专有的金属纳米微粒复合技术开发出新型导电性纤维。该产品是通过聚乙烯醇分子的羟基与各种金属离子的相互作用,在纤维内部形成硫化铜纳米粒子的高导电性聚乙烯醇纤维。通过对纳米尺寸的金属微粒进行     

The effects of confinement inside carbon nanotubes on catalysis

The unique tubular morphology of carbon nanotubes (CNTs) has triggered wide research interest. These structures can be used as nanoreactors and to create novel composites through the encapsulation of guest materials in their well-defined channels. The rigid nanotubes restrict the size of the encapsulated materials down to the nanometer and even the sub-nanometer scale. In addition, interactions may develop between the encapsulated molecules and nanomaterials and the CNT surfaces. The curvature of CNT walls causes the π electron density of the graphene layers to shift from the concave inner to the convex outer surface, which results in an electric potential difference. As a result, the molecules and nanomaterials on the exterior walls of CNTs likely display different properties and chemical reactivities from those confined within CNTs. Catalysis that utilizes the interior surface of CNTs was only explored recently. An increasing number of studies have demonstrated that confining metal or metal oxide nanoparticles inside CNTs often leads to a different catalytic activity with respect to the same metals deposited on the CNT exterior surface. Furthermore, this inside and outside activity difference varies based on the metals used and the reactions catalyzed. In this Account, we describe the efforts toward understanding the fundamental effects of confining metal nanoparticles inside the CNT channels. This research may provide a novel approach to modulate their catalytic performance and promote rational design of catalysts. To achieve this, we have developed strategies for homogeneous dispersion of nanoparticles inside nanotubes. Because researchers have previously demonstrated the insertion of nanoparticles within larger nanotubes, we focused specifically on multiwalled carbon nanotubes (MWCNTs) with an inner diameter (i.d.) smaller than 10 nm and double-walled carbon nanotubes (DWCNTs) with 1.0-1.5 nm i.d. The results show that CNTs with well-defined morphology and unique electronic structure of CNTs provide an intriguing confinement environment for catalysis.     

Synthesis of vertically aligned carbon nanotubes on metal deposited quartz plates

Without plasma aid, we have successfully synthesized vertically aligned carbon nanotubes (CNTs) on iron-, cobalt- or nickel-deposited quartz plates by chemical vapor deposition with ethylenediamine as a precursor. The amine serves as both etching reagent for the formation of metal nanoparticles and carbon source for the growth of aligned carbon nanotubes. The carbon nanotubes were vertically aligned in high density on a large area of the plain silica substrates. The density and diameter of CNTs is determined by the thickness of the deposited metal film and the length of the tubes can be controlled by varying the reaction time. High-resolution transmission electron microscopy analysis reveals that the synthesized CNTs are multiwalled with a bamboo-like structure. Energy dispersive X-ray spectra demonstrate that the CNTs are formed as tip growths. Raman spectrum provides definite evidence that the prepared CNTs are multiwalled graphitic structure.     

Fabrication of metal nanoparticles on highly dispersed pristine carbon nanotubes

A convenient approach to fabricate metal (i.e. gold, platinum, and palladium) nanoparticles on highly dispersed pristine carbon nanotubes (CNTs) was developed using a conjugated block copolymer of poly(3-hexylthiophene)-b-poly(vinylpyrrolidone) (P3HT-b-PVP). P3HT-b-PVP not only provides a stable dispersion of pristine CNTs through the π–π interactions between P3HT block and CNTs, but also introduces PVP groups on CNT surfaces to induce the heterogeneous nucleation of metal nanoparticles and protect them from aggregating. The density of metal nanoparticles on CNT surfaces was controlled by the metal salt/CNT feed ratio. The simple processing procedure, versatility in synthesizing various metal nanoparticles, high metal nanoparticle loading capacity, and excellent dispersibility and processability of the product make this approach a promising method to fabricate metal nanoparticles on CNTs.     

Metal catalyst residues in carbon nanotubes decrease the thermal stability of carbon nanotube/silicone composites

An anomalous decrease in the thermal stability of silicone was observed when carbon nanotubes (CNTs) were added as fillers. The decreased thermal stability is found to result from the residues of cobalt nanoparticles in CNTs, whereas CNTs synthesized with other metal catalysts do not show such a phenomenon. The analysis of thermal degradation products indicates that CNT fillers do not change the mechanism of the thermal degradation of silicone but cobalt nanoparticles within CNTs may accelerate the degradation through free radical generation. Radical scavengers such as hindered amines and impurity-free CNTs, or removal of cobalt nanoparticles by acid treatment, can mitigate the accelerated thermal degradation.     

The new age of carbon nanotubes: an updated review of functionalized carbon nanotubes in electrochemical sensors

Since the discovery of carbon nanotubes (CNTs), they have drawn considerable research attention and have shown great potential application in many fields due to their unique structural, mechanical, and electronic properties. However, their native insolubility severely holds back the process of application. In order to overcome this disadvantage and broaden the scope of their application, chemical functionalization of CNTs has attracted great interest over the past several decades and produced various novel hybrid materials with specific applications. Notably, the rapid development of functionalized CNTs used as electrochemical sensors has been successfully witnessed. In this featured article, the recent progress of electrochemical sensors based on functionalized CNTs is discussed and classified according to modifiers covering organic (oxygen functional groups, small organic molecules, polymers, DNA, protein, etc.), inorganic (metal nanoparticles, metal oxide, etc.) and organic-inorganic hybrids. By employing some representative examples, it will be demonstrated that functionalized CNTs as templates, carriers, immobilizers and transducers are promising for the construction of electrochemical sensors.     

Modified carbon nanotubes: an effective way to selective attachment of gold nanoparticles

Through various modifications of carbon nanotubes (CNTs), gold nanoparticles were selectively attached to the nanotube and the locations of functional groups were further confirmed. Using cationic polyethyleneamine or anionic citric acid as the dispersant, the surface properties of CNTs could be changed to yield a basic or acidic surface. By electrostatic interaction, the CNTs could be successfully coated with about 10 nm gold nanoparticles. After heat treatment in NH₃, about 1–2 nm gold nanocluster-filled nanotubes were achieved. This shows that the heat treatment with NH₃ could make CNTs open-ended and generate functional basic groups on the inner wall of the nanotubes.     

Study of carbon nanotubes synthesis by spray pyrolysis and model of growth

Multi-walled carbon nanotubes (MWCNTs) were grown inside of quartz tubing by spray pyrolysis of ferrocene/benzene under argon flow. Carbon nanotubes (CNTs) with length of 200 μm were produced with reaction time of 10 min. The diameter of CNTs was influenced by the size of droplets formed in the nebulizer and the length was greatly influenced by ferrocene concentration and argon gas flow. It was found that temperature is a critical variable to produce CNTs at the experimental conditions used in this work. It was also found that CNTs only grew if ferrocene is added to gas flow, even if CNTs are previously seeded and formed on substrate, benzene cannot produce the CNTs without ferrocene. A model of CNTs formation and growth is proposed for spray pyrolysis of ferrocene/benzene, this mechanism consist of the formation of carbon/Fe nanoparticles during pyrolysis in the gas phase, these nanoparticles reach the walls of substrate, and the nanoparticles attach to substrate surface or to the nanotubes. Under proper conditions the displacement of Fe inside the graphitic structure induces the alignment of carbon walls, straightening this way the nanotubes.     

Carbon-nanotube-assisted transmission electron microscopy characterization of aerosol nanoparticles

Aerosol nanoparticles draw great attention due to their unique physico-chemical properties that can be harnessed for innovative applications as well as for their potential impact on public health and the environment. Microscopic characterization of these particles is critically important to understand the unique particle properties and their interaction with biological systems. Here we report on a simple and efficient method for size, morphology, and crystallinity analyses of aerosol nanoparticles through transmission electron microscopy (TEM). The method uses carbon nanotubes (CNTs) as the particle support on conventional TEM grids. The CNT support significantly improves the quality of high resolution TEM (HRTEM) imaging due to the unique properties of CNTs, the high probability of particles sitting at the edge of CNTs, and the minimization of the interference interaction between the electron beam and the supporting substrate. The improved HRTEM images are useful for detailed characterization of nanoparticles, and particularly suitable for analyzing core-shell nanoparticles.     

Effect of noncovalent chemical modification on the electrical conductivity and tensile properties of poly(methyl methacrylate)/carbon nanotube composites

Noncovalent chemical modification by initiated chemical vapor deposition technique is applied to carbon nanotubes (CNTs) to reduce average agglomerate size of the nanoparticles in the polymer matrix and to improve surface interaction between the composite constituents. CNT surfaces are coated conformally with thin poly(glycidyl methacrylate) (PGMA) polymer film and coated nanoparticles are incorporated in poly(methyl methacrylate) (PMMA) polymer matrix using solvent casting technique. Conformal PGMA coatings around individual nanotubes were identified by scanning electron microscopy analysis. Transmission electron microscopy and optical microscopy analyses show homogeneous composite morphology for composites prepared by using PGMA coated nanotubes. Fourier Transform Infrared and X‐ray photoelectron spectroscopy analyses show the successful deposition of polymer with high retention of epoxide functionality. PGMA coating of CNTs exhibits improvement in electrical conductivity and tensile properties of PGMA‐CNT/PMMA systems when compared with uncoated nanoparticles. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Zn based nanoparticle–carbon nanotube hybrid materials: Interaction and charge transfer

The interaction and charge transfer between Zn-based nanoparticles (NPs) and carbon nanotubes (CNTs) is investigated by X-ray Auger and photoelectron spectroscopy. Charge transfer from Zn NPs toward the CNTs is demonstrated by the presence of an additional feature revealed in the C 1s spectrum of CNTs. This charge transfer was found to vanish after thermal oxidation due to the transformation of the metal Zn into ZnO. Photoluminescence (PL) spectroscopy shows that in the samples ZnO(Nps)/CNTs the PL intensity is quenched.