一种新型空心镍纳米球的合成及其性能

以二氧化硅颗粒作为模板、金纳米颗粒作为表面晶种的方法制备了壳厚度可控的镍空心球。得到的空心镍纳米球是由似针状的面心立方的镍纳米颗粒构成的,碱溶液处理过程不影响镍纳米壳的形貌。高温处理显示镍空心球具有良好的热稳定性。研究了镍空心球电催化氧化甲醇和乙醇的活性,结果显示在碱性溶液中镍空心球是一种非常高效的甲醇和乙醇电催化氧化剂。     

纳米金属氧化物粉体的液相制备和表征进展

根据国内外研究者的报道及作者近几年来对纳米金属氧化物的制备研究结果,介绍了纳米金属氧化物液相法制备中常用的方法及表征手段,并探讨了纳米粉体制备过程中的团聚和反团聚措施。     

CdSe/SiO_2异质复杂纳米结构的可控制备

复杂纳米结构至今依然是材料领域研究的前沿。采用简单的气相合成法,通过反应温度选择和初始反应物配方设计,实现了复杂形貌CdSe/SiO2异质纳米结构的可控制备,在直径为100nm左右的一维纳米棒端部成功嫁接了直径约400nm的碗状SiO2纳米空心球。通过XRD,FESEM,HRTEM,EDS和SAED等手段分析试样的形貌、成分和晶体学特征。XRD测试表明,生成产物是CdSe和SiO2的复合材料;EDS分析进一步确认一维纳米棒和碗状空心球的化学成分分别为CdSe和SiO2;HRTEM和SAED测试表明,CdSe纳米棒是沿[0002]方向生长的单晶结构,SiO2纳米空心球为非晶结构。这种新奇的异质纳米结构可以作为未来纳米靶向药物的载体材料。     

聚苯胺低维纳米结构的研究现状

综述了聚苯胺低维纳米结构在制备方法、形成机理以及功能特性等方面的研究现状。重点阐述了聚苯胺纳米管、纳米纤维的制备方法,包括模板法、界面法、自组装法、电化学法等,同时简要介绍了聚苯胺纳米管、纳米纤维的生长机理,展望了其在生物传感器、纳米电子器件、电致变色材料、复合材料等方面的应用前景。总结了聚苯胺低维纳米结构方面的最新研究进展,如聚苯胺纳米空心球、网状结构、菊花状结构、螺旋结构以及聚苯胺薄膜等的制备方法及特性,展望了其潜在的应用领域和广阔的发展前景。     

纳米粒子掺杂的液晶显示技术

液晶显示器需要快速响应来显示动态画面,纳米粒子掺杂技术能够改善液晶材料的特性,提高液晶显示器的光电性能。本文介绍了四种主要的掺杂纳米粒子类型:碳纳米管、金属纳米粒子、金属氧化物纳米粒子和铁电性纳米粒子。     

纳米压印技术

传统光学光刻技术的高成本促使科学家去开发新的非光学方法,以取代集成电路工厂目前所用的工艺.另外,微机电系统(MEMS)的成功启发科学家借用MEMS中的相关技术,将其使用到纳米科技中去,这是得到纳米结构的一种有效途经.纳米压印在过去的几年里受到了高度重视,因为它成功地证明了它有成本低、分辨率高的潜力.纳米压印技术主要包括热压印、紫外压印(含步进-闪光压印)和微接触印刷等.本文详细讨论纳米压印材料的制备及常用的三种工艺的工艺步骤和它们各自的优缺点.并对这三种工艺进行了比较.最后列举了一些典型应用,如微镜、金属氧化物半导体场效应管、光栅等.     

纳米级CMOS集成电路的发展状况及辐射效应

介绍互补金属氧化物半导体(CMOS)集成电路的发展历程及纳米级CMOS集成电路的关键技术,在此基础上研究了纳米级CMOS集成电路的辐射效应及辐射加固现状。研究结果表明,纳米级FDSOICMOS集成电路无需特殊的加固措施,却比相同技术代的体硅CMOS集成电路有好得多的辐射加固能力,特别适用于空间应用环境。     

我国科学家研制出性能优异的纳米空心球

<正>据悉,中科院上海硅酸盐所研究员高濂带领的课题组用一种简单通用的方法,通过控制实验条件,在温和的反应条件下获得了氧化锌纳米棒束、空心球结构,这些材料具有比较均匀的尺寸和良好的发光性能。在纳米     

氧化铟空心球的合成及其气敏性能研究

采用溶剂热–退火反应法合成了氧化铟空心球。所获空心球用XRD,TEM和SEM等表征。发现所合成的氧化铟空心球直径介于0.5~1.0μm,且该空心球是由粒径约50nm的氧化铟纳米块堆积而成。研究了用此空心球制备的气敏元件的气敏性能。结果表明,氧化铟空心球结构有益于提高元件的响应性能。此外,该元件对NO2气体有较快的响应(8s)并且恢复时间较短(15s)。     

纳米稀土复合材料——汽车尾气的克星

在召开的海峡两岸纳米颗粒学术研讨会上，韶关学院的专家就“纳米复合材料在汽车排气净化中的应用研究”做了专题报告，专家在实验中将制好的纳米复合催化剂涂在堇青石峰窝陶瓷载体上，安装在发动机排气管内进行试验。结果表明：纳米复合催化剂比传统的三元催化转化器降低了CO排放35％、HC排放30％、NOx排放22％。一系列实验数据证明了运用纳米技术净化汽车尾气的可行性，稀土纳米粒子和部分纳米贱金属氧化物具有较好催化作用，利用这些资源制造发动机排气净化材料，具有良好的经济和社会效应，     

Synthesis of Spheres with Complex Structures Using Hollow Latex Cages as Templates

Hollow latex cages (HLCs) are used as templates to fabricate composite hollow spheres with complex structures. The template HLCs have a polystyrene shell with transverse hydrophilic channels connecting to an interior hydrophilic surface. They are stable and permeable, and a reagent can be preloaded into the cavity reservoir. The interior hydrophilic surface is conducive to a favorable inward synthesis. By simply altering the loading sequence of reagents and their concentration, the morphology of the composite spheres can be tuned. For example, during the formation of titania composite spheres by a sol–gel process using tetrabutyl titanate (TBT), composite hollow spheres with titania pillars protruding from the surface are predominantly created, owing to the formation of titania within the hydrophilic channels when the HLCs, preloaded with water, are immersed into TBT at an appropriate concentration. When the TBT concentration is decreased, the size of the pillars decreases accordingly until they disappear, leading to a smooth outer surface. Conversely, when HLCs loaded with TBT are immersed into water, titania forms only on the interior hydrophilic surface and not within the channels, resulting in composite hollow spheres with smooth outer surfaces. The composite spheres can be further used as templates to grow material on the outer surface, and double‐shelled hollow spheres of various compositions are achieved. Macroporous materials with unique morphologies—for example, hollow spheres embedded within the pores—have been derived by using an array template of the composite spheres. The method can be applied to a diversity of inorganic materials, metals, oxides, semiconductors, and functional polymers.     

Preparation of Hollow Zeolite Spheres and Three‐Dimensionally Ordered Macroporous Zeolite Monoliths with Functionalized Interiors

A novel and flexible strategy involving hydrothermal transformation of guest‐incorporated zeolite‐seeded mesoporous silica spheres was proposed to prepare guest‐encapsulated hollow zeolite spheres and three‐dimensionally (3D) ordered macroporous zeolite monoliths. The guest species that were pre‐incorporated into the mesopores of silica spheres could be spontaneously encapsulated inside the formed hollow zeolite shells by consuming silica nutrition of the original mesoporous silica cores during the hydrothermal process. A wide range of guest materials with a size ranging from nanometers to micrometers, e.g., Ag and PdO nanoparticles, and mesoporous spheres of carbon and polymer of micrometer size were successfully encapsulated into both discrete hollow zeolite spheres and 3D ordered macroporous zeolite monoliths. Such materials are expected to find a variety of applications such as catalysis, adsorption, and novel microreactors for their special structures with active species inside and zeolitic porous shell outside.     

Synthesis of Nickel Sulfide Submicrometer‐Sized Hollow Spheres Using a γ‐Irradiation Route

Nickel sulfide (NiS) hollow spheres have been successfully synthesized by γ‐irradiation, at room temperature, of an aqueous PMMA–CS₂–ethanol solution that contains NiSO₄·6H₂O. Electron microscopy results show that the diameter of the NiS hollow spheres and the thickness of the sphere shells are about 500 nm and 20 nm, respectively. The room‐temperature UV‐vis absorption spectrum of the NiS hollow spheres gives a peak centered at around 233 nm (5.56 eV) with a remarkable blue‐shift relative to that of bulk NiS (2.1 eV). This remarkable blue‐shift may be attributed to the small dimensions of the materials. A possible growth mechanism of NiS hollow spheres by γ‐irradiation method is also presented. The successful preparation of NiS hollow spheres on a large scale under mild conditions could be of interest for both applications and fundamental studies.     

Nanometer‐Sized Copper Sulfide Hollow Spheres with Strong Optical‐Limiting Properties

CuS semiconductor nanometer‐sized hollow spheres are successfully synthesized by using a soft‐template method. A possible growth mechanism is proposed. The linear optical property of the CuS hollow spheres is examined by means of photoluminescence spectroscopy at room temperature. The optical‐limiting (OL) property of these nanostructures is characterized by using a nanosecond Q‐switched YAG laser and an optical parametric oscillator pumped with Surelite‐III. A strong OL response is detected for the CuS hollow spheres in both visible and near infrared (NIR) spectral ranges, which makes these promising materials for applications such as the protection of human eyes or as optical sensors for high‐power laser irradiation. The OL mechanism of the CuS hollow‐sphere nanostructure may be the combination of free‐carrier absorption (FCA) and nonlinear scattering.     

Hybrid ZnO–Dye Hollow Spheres with New Optical Properties by a Self‐Assembly Process Based on Evans Blue Dye and Cetyltrimethylammonium Bromide

A facile one‐step process for the fabrication of hybrid ZnO–dye hollow spheres with novel optical properties has been discovered. Addition of Evans blue (EB) dye to cetyltrimethylammonium bromide (CTAB) results in the formation of CTAB‐EB micelles through an ionic self‐assembly process, and the resulting material acts as a soft template for the crystallization of ZnO upon addition of a zinc salt and ammonia under mild refluxing conditions. The formation mechanism of such hollow spheres has been investigated. These new hybrid ZnO–dye hollow spheres display distinct optical properties that differ from properties observed for the pure ZnO and dye components. This approach is a new and effective method for fabricating novel semiconductor–dye hybrids with unique electronic and optical properties and is expected to provide access to additional inorganic–organic materials with novel structures and unusual functionalities.     

MS2 (M = Co and Ni) Hollow Spheres with Tunable Interiors for High‐Performance Supercapacitors and Photovoltaics

We demonstrate in this paper facile synthesis of CoS₂ and NiS₂ hollow spheres with various interiors through a solution‐based route. The obtained CoS₂ microspheres constructed by nanosheets display a three‐dimensional architecture with solid, yolk‐shell, double‐shell, and hollow interiors respectively, with continuous changes in specific surface areas and pore‐size distributions. Especially, the CoS₂ hollow spheres demonstrate excellent supercapacitive performance including high specific capacitance, good charge/discharge stability and long‐term cycling life, owing to the greatly improved faradaic redox reaction and mass transfer. Furthermore, CoS₂ hollow spheres exhibit superior electrocatalytic activity for disulfide/thiolate (T₂/T^?) redox electrolyte in dye‐sensitized solar cells (DSCs). Therefore, this work provides a promising approach for the design and synthesis of structure tunable materials with largely enhanced supercapacitor behavior, which can be potentially applied in energy storage devices.     

Template‐Free Preparation of Hollow Sb2S3 Microspheres as Supports for Ag Nanoparticles and Photocatalytic Properties of the Constructed Metal–Semiconductor Nanostructures

A simple and convenient Ostwald ripening route to the morphology‐ and phase‐controlled preparation of hollow Sb₂S₃ microspheres is developed. The hollow spheres are clusters of smaller microspheres if orange amorphous Sb₂S₃ colloid is used as the precursor, whereas, if starting from the yellow precursor, the products are regular hollow spheres. By selecting appropriate experimental conditions for ripening, the phase of the hollow Sb₂S₃ microspheres can be controlled. Amorphous and orthorhombic hollow spheres are prepared by ripening the colloidal precursors at ambient temperature and in an autoclave, respectively. The closed shell of hollow Sb₂S₃ spheres can be easily eroded by hydrochloric acid to form an open structure. By the in situ reduction of adsorbed Ag⁺ on the surface and interior of the hollow spheres, Ag nanoparticles are introduced into them, to form functional metal–semiconductor composites, the weight content of which is controlled by regulating the concentration of the Ag⁺ source and the adsorption time. The composite structures composed of Ag nanoparticles and hollow Sb₂S₃ spheres exhibit a remarkably enhanced absorption covering the UV and visible regions of the electromagnetic spectrum. A study of the photocatalytic properties of the composite structures demonstrates that exposure to both UV and visible light enables them to induce the rapid decomposition of 2‐chlorophenol. The degradation rate increases with a larger weight content of Ag in the composite structure.     

Replication and Coating of Silica Templates by Hydrothermal Carbonization

Hierarchical carbon materials with functional groups residing at the surface are prepared for the first time by using nanostructured silica materials as templates in combination with hydrothermal carbonization at mild temperatures (180 °C). Different carbon morphologies (e.g., macroporous casts, hollow spheres, carbon nanoparticles, and mesoporous microspheres) can be obtained by simply altering the polarity of the silica surface. The surface functionality and hydrophilicity of the resulting materials are assessed by Fourier transform IR spectroscopy, X‐ray photoelectron analysis, and water porosimetry. Raman spectroscopy and X‐ray diffraction measurements show that the materials are of the carbon‐black type, similar to charcoal.