高温液相还原法制备钴纳米晶及其二维有序阵列

由于小尺寸效应,纳米晶具有独特的电、磁、光学和结构性质,因而在材料领域具有广阔的应用前景,例如,利用磁性金属和半导体纳米晶对尺寸敏感的特性进行超高密度信息磁存储及微电子技术的应用研究．但表面原子的巨大剩余成键能力使其倾向于相互团聚并长大,只有实现纳     

原位生长技术制备石墨烯强化铜基复合材料

利用等离子增强化学气相沉积方法,在铜粉表面原位生长了站立石墨烯,用于制备石墨烯强化铜基复合材料.研究表明,石墨烯包覆在铜粉外表面,微观尺度实现了两者的均匀混合;生长的初期阶段,碳、氢等离子基团可将铜粉表面的氧化层还原,有助于铜粉-石墨烯之间形成良好的界面;石墨烯的成核是一个生长/刻蚀相互竞争的过程,其尺寸可受制备温度调控.利用放电等离子烧结方法将粉末压制成型,测试结果显示,添加石墨烯样品的电阻率降低了一个数量级,维氏硬度和屈服强度分别提高了15.6%和28.8%.     

液相法制备金属纳米粒子

液相法是在均相溶液中，利用各种途径引发化学反应，通过均相或异相成核及随后的扩散生长而制备出粒径分布窄且表面功能化的纳米尺度材料．介绍了液-液两相法、反相胶束、高温液相法等制备单分散金属纳米粒子的方法和高温液相法制备金属纳米粒子的影响因素，以及近年来在金属纳米粒子的制备和性能研究上的进展，尤其是Co等多种磁性纳米粒子的制备、磁性研究．     

Controlled growth of large＇scale silver nanowires

Large-scale silver nanowires with controlled aspect ratio were synthesized via reducing silver nitrate with 1, 2- propanediol in the presence of poly （vinyl pyrrolidone） （PVP）. Scanning electron microscopy, transmission electron microscopy and x-ray powder diffraction were employed to characterize these silver nanowires. The diameter of the silver nanowires can be readily controlled in the range of 100 to 400 nm by varying the experimental conditions. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy results show that there exists no chemical bond between the silver and the nitrogen atoms. The interaction between PVP and silver nanowires is mainly through the oxygen atom in the carbonyl group.     

阳极氧化铝模板表面自组织条纹的形成

对未经化学抛光处理的Al进行阳极氧化得到阳极氧化铝模板，发现Al表面形成了条纹与多孔阵列共存的自组织结构，用原子力显微镜对这种结构进行了研究.借助Brusselator模型对条纹的形成机理进行了讨论，认为条纹图案是Al表面氧化层/电解液界面的Al₂O₃在整个反应过程中的生成和溶解两个过程相互竞争导致的，只有在特定的反应条件才会出现高度有序的结构. 关键词： 氧化铝模板（AAO） 原子力显微镜（AFM） 自组织条纹 Brusselator模型     

Anomalous aggregation growth of palladium nanosphere with SPR band in visible range

The morphology and properties of nanostructures are significantly influenced by the chemical coordination during their growth procedure. Using small molecule N-vinyl pyrolidone as stabilizer, this paper introduces a new strategy for synthesis of palladium nanospheres, which has a novel surface plasmon resonance band in the visible range. An aggregation growth mode was observed in the growth process. More specifically, the growth rate increases with increasing concentration of stabilizer. The absorption in visible region suggests new optical applications for these Pd nanospheres, such as photocatalysis, photothermal heating and surface enhanced Raman scattering.     

Formation and photoluminescence properties of boron nanocones

This paper reports that a simple chemical vapour deposition method has been adopted to fabricate large scale, high density boron nanocones with thermal evaporation of B/B2O3 powders precursors in an Ar/H2 gas mixture at the synthesis temperature of 1000-1200℃. The lengths of boron nanocones are several micrometres, and the diameters of nanocone tops are in a range of 50-100 nm. transmission electron microscopy and selected area electron diffraction indicate that the nanocones are single crystalline α-tetragonal boron. The vapour liquid solid mechanism is the main formation mechanism of boron nanocones. One broad photolumineseence emission peak at the central wavelength of about 650 nm is observed under the 532 nm light excitation. Boron nanocones with good photoluminescence properties are promising candidates for applications in optical emitting devices.     

TEM study on hollow and prepared from porous Cu20 nanoparticles solution phase

In this paper, hollow and porous Cu2O nanoparticles were prepared by adjusting the cationic surfactant cetyltrimethylammonium （CTAB） concentration in the solution-phase reaction. Structural investigations reveal that Cu2Onanoparticles can be either well-defined hollow nanoboxes or porous nanocubes depending on the synthesis conditions. The transmission electron microscopy （TEM） observations demonstrated that the nanoparticles in general are composed of small grains coherently growing along certain preferred orientations.     

Synthesis and photoluminescence property of boron carbide nanowires

Large scale, high density boron carbide nanowires have been synthesized by using an improved carbothermal reduction method with B/B203/C powder precursors under an argon flow at 1100℃. The boron carbide nanowires are 5-10 μm in length and 80-100 nm in diameter. Transmission electron microscopy （TEM） and selected area electron diffraction （SAED） characterizations show that the boron carbide nanowire has a B4C rhombohedral structure with good crystallization. The Raman spectrum of the as-grown boron carbide nanowires is consistent with that of a B4C structure consisting of B11C icosahedra and C-B-C chains. The room temperature photoluminescence spectrum of the boron carbide nanowires exhibits a visible range of emission centred at 638 nm.     

Synthesis of monodisperse palladium nanocubes and their catalytic activity for methanol electrooxidation

The single crystalline palladium nanocubes with an average size of 7 nm were prepared in the presence of poly (vinyl pyrrolidone) (PVP) and KBr using the polyol method. The as-prepared Pd nanocubes were highly uniform in both size and shape. The ordered packing structures including monolayer and multilayer can be fabricated via the rate-controlled evaporation of solution solvent. The electrochemical catalytic activity of these Pd nanocubes towards methanol oxidation was found to be higher than that of spherical Pd nanoparticles of similar size.