CuO纳米结构阵列的简易合成及其光催化性质

利用一种简便的一步反应路线, 通过调节反应温度, 选择性地合成出两种有序排列的氧化铜纳米阵列, 即成束的一维(1D)纳米带和紧密排列的二维(2D)纳米片. 系统研究了产物的物相和形貌随反应时间的演变情况, 结果表明两种氧化铜纳米结构阵列分别是通过氧化→生长→脱水和氧化→脱水→生长过程形成的, 其中动力学因素控制的成核与生长过程决定了氧化铜纳米结构的最终形貌. 模拟太阳光辐射光催化降解有机染料罗丹明B(RhB), 测试了所制备的氧化铜纳米结构阵列的光催化活性. 本工作为制备新颖的多级纳米结构材料提供了一种简单且经济的合成路线, 这些纳米材料将在多个领域体现出重要的应用潜力.     

Shape-controlled synthesis and self-assembly of hexagonal covellite (CuS) nanoplatelets

Single-crystalline, hexagonal covellite (CuS) nanoplatelets were successfully synthesized through a facile, inexpensive, reproducible, and improved solvothermal process in toluene at 120 degrees C for 24 h with hexadecylamine as a capping agent and copper acetate and carbon disulfide as precursors. These nanoplatelets are about 26+/-1.5 nm in diameter and 8+/-1.2 nm thick, and have a tendency to self-assemble into pillarlike nanostructures with face-to-face stacks, raftlike nanostructures with side-by-side arrays, and stratiform nanostructures with layer-by-layer self-assembly. The crystal shape, morphology, and crystallographic orientation of the covellite obtained were investigated by means of XRD, TEM, and high-resolution TEM, and a potential self-assembly mechanism was proposed.     

基于叶片状氧化铜纳米材料的无酶葡萄糖传感电极

将Nafion交联剂与纳米材料修饰至玻碳电极基底制备一种无酶葡萄糖传感器,通过循环伏安曲线、时间-电流曲线检测该电极电化学特性. 氧化铜纳米复合膜具有高比表面积和多活性点位的优点. 实验结果表明,氧化铜纳米电极对葡萄糖的检测线性响应范围0.01 ~ 0.3 mmol·L^-1,灵敏度1783.58 μA·L·mmol^-1·cm^-2,检测限0.80 μmol·L^-1 (S/N=3),稳定性较好,能抵抗抗坏血酸、多巴胺和尿酸干扰.     

Synthesis of nano/micro zinc oxide rods and arrays by thermal evaporation approach on cylindrical shape substrate

Nano and micro ZnO rods and arrays have been synthesized by a simple thermal evaporation approach on a cylindrical shape substrate. Most of the synthesized ZnO products are single crystalline with a hexagonal structure and grow along the [0001] direction. Individual protrusive ZnO rods and well-aligned arrays are two typical products in our work. The individual protrusive ZnO rods have diameters of 25 nm approximately 2.1 microm and lengths from several hundred nanometers to 40 microm, while in the well-aligned arrays, the diameter and length of each ZnO rod range from 60 nm to 1.2 microm and from 4 microm to 6 microm, respectively. The heating temperature and deposition position are two key points to control the diameters of the rods. The growth mechanism is discussed and proposed. The perfect crystalline ZnO rods with different scales from nanometer to micrometer are good models for the investigation of the size effect of physical and chemical properties of one-dimensional material.     

化学溶液沉积法制备单分散氧化锌纳米棒阵列

在由溶胶凝胶法制备的纳米ZnO薄膜基底上, 采用化学溶液沉积法制备了单分散、高度取向的ZnO纳米棒阵列膜. 通过控制纳米ZnO薄膜的制备工艺, 可以调节氧化锌纳米棒的直径. 利用FESEM, TEM, HRTEM, SAED和XRD表征了氧化锌纳米棒阵列的形貌和晶体结构. ZnO纳米棒的室温PL谱具有很高的紫外带边发射峰, 在可见光波段无发射峰, 表明该方法制备的ZnO纳米棒晶体结构完整, 晶体中O空位的浓度很低.     

Structural,morphological, optical and antibacterial properties of pentagon CuO nanoplatelets

Pentagon copper oxide (CuO) nanoplatelets formation employing Nephelium lappaceum L. extract was successfully developed. Characteristic X-ray diffraction peaks revealed a monoclinic and end-centered lattice structure of copper oxide belonging to ¹C⁶_2h (c²/c) space group. Three characteristic Raman peaks, A_g, B_g(1) and B_g(2), confirmed the monoclinic CuO structure. The pentagon CuO nanoplatelets formation increased proportionally with increase in calcination temperature from 600 to 800?°C and the particle size was noticeably increased from 30 to 250?nm. Strong photoluminescence emission peak was noticed in the UV region between 377 and 393?nm. The metal–oxygen Cu²⁺–O^2? vibration of the synthesized product in the range between 300 and 700?cm^?1 was confirmed using infrared studies. The CuO product obtained at 600?°C showed best antibacterial action due to its small particle size (30–60?nm) against both Gram-positive and Gram-negative bacteria. The obtained product cell morphology, proliferation and viability test were investigated with respect to control and 10, 50, 100, and 500?μg/ml. Cell viability of the product were respectively 74, 55.3, 50, and 27.3% and found suitable for biomedical applications.

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Preparation and Photoluminescence of ZnO Comb-Like Structure and Nanorod Arrays

A large quantity of Zinc oxide (ZnO) comb-like structure and high-density well-aligned ZnO nanorod arrays were prepared on silicon substrate via thermal evaporation process without any catalyst. The morphology, growth mechanism, and optical properties of the both structures were investigated using XRD, SEM, TEM and PL. The resulting comb-teeth, with a diameter about 20 nm, growing along the 0001 direction have a well-defined epitaxial relationship with the comb ribbon. The ZnO nanorod arrays have a diameter about 200 nm and length up to several micrometers growing approximately vertical to the Si substrate. A ZnO film was obtained before the nanorods growth. A growth model is proposed for interpreting the growth mechanism of comb-like zigzag-notch nanostructure. Room temperature photoluminescence measurements under excitation wavelength of 325 nm showed that the ZnO comb-like nanostructure has a weak UV emission at around 384 nm and a strong green emission around 491 nm, which correspond to a near band-edge transition and the singly ionized oxygen vacancy, respectively. In contrast, a strong and sharp UV peak and a weak green peak was obtained from the ZnO nanorod arrays.     

CuInSe(2) ultrathin nanoplatelets: novel self-sacrificial template-directed synthesis and application for flexible photodetectors

Non-layered chalcopyrite-type CuInSe(2) nanoplatelets, with thickness down to 2 nm, have been synthesized for the first time. The ultrathin nanoplatelets are of benefit for low-cost and high performance flexible photodetectors.     

From layered double hydroxide to spinel nanostructures: facile synthesis and characterization of nanoplatelets and nanorods

Mg-Al spinel (MgAl2O4) nanorods and nanoplatelets transformed from Mg-Al layered double hydroxide (Mg-Al-LDHs) were synthesized via a combined hydrothermal method and calcination route using Al(NO3).9H2O and Mg(NO3)2.6H2O as raw materials. The nanorods and nanoplatelets were characterized by means of physical techniques, including powder X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microcopy (HRTEM), selected-area electron diffraction (SAED), Fourier transform infrared spectra (FT-IR), thermogravimetric (TG), and nitrogen adsorption-desorption isotherms. XRD patterns reveal that the Mg-Al-LDHs nanostructures were obtained under a hydrothermal reaction temperature of 200 degrees C and Mg-Al spinel nanostructures were fabricated via calcination of the Mg-Al-LDHs nanostructures at 750 degrees C. It can be seen from TEM that the sizes of the Mg-Al-LDHs nanoplatelets were about 20-40 nm and the diameters of the MgAl2O4 nanorods were ca. 6 nm. The HRTEM images indicate that the crystal lattice spaces of the MgAl2O4 nanorods and nanoplatelets are 0.282 and 0.287 nm, respectively.     

Optimization of processing parameters on the controlled growth of ZnO nanorod arrays for the performance improvement of solid-state dye-sensitized solar cells

High-transparency and high quality ZnO nanorod arrays were grown on the ITO substrates by a two-step chemical bath deposition (CBD) method. The effects of processing parameters including reaction temperature (25-95 °C) and solution concentration (0.01-0.1 M) on the crystal growth, alignment, optical and electrical properties were systematically investigated. It has been found that these process parameters are critical for the growth, orientation and aspect ratio of the nanorod arrays, showing different structural and optical properties. Experimental results reveal that the hexagonal ZnO nanorod arrays prepared under reaction temperature of 95 °C and solution concentration of 0.03 M possess highest aspect ratio of ∼21, and show the well-aligned orientation and optimum optical properties. Moreover the ZnO nanorod arrays based heterojunction electrodes and the solid-state dye-sensitized solar cells (SS-DSSCs) were fabricated with an improved optoelectrical performance.     

Si nanowire semisphere-like ensembles as field emitters

Silicon nanowires assembled in micro-sized semispheres were synthesized through simple thermal evaporation without using any templates and metal particle catalysts; electron microscopy revealed that the nanowires within semisphere ensembles are well-aligned and evenly distributed; a typical nanowire array density was of approximately 4 x 10(9) cm(-2); field-emitting characteristics of the arrays were analyzed.     

Growth of millimeter-long and horizontally aligned single-walled carbon nanotubes on flat substrates

Millimeter-long and well-aligned single-walled carbon nanotubes (SWNTs) have been produced on silica/silicon surfaces using the carbon monoxide chemical vapor deposition (CO-CVD) method. The orientation of the nanotube arrays can be well-controlled by the gas flow during the growth. The majority of the orientated SWNTs are straight and individual. The length of the nanotubes can be >2 mm for a 10 min growth. Furthermore, multidimensional crossed-networks of SWNT can be easily generated by multistep processes. These results present a great opportunity in the controllable production of organized SWNT arrays for large-scale carbon nanotube-based nanodevice fabrication.     

Controllable synthesis and optical properties of novel ZnO cone arrays via vapor transport at low temperature

Novel ZnO cone arrays with controllable morphologies have been synthesized on silicon (100) substrates by thermal evaporation of metal Zn powder at a low temperature of 570 degrees C without a metal catalyst. Clear structure evolutions were observed using scanning electron microscopy: well-aligned ZnO nanocones, double-cones with growing head cones attached by stem cones, and cones with straight hexagonal pillar were obtained as the distance between the source and the substrates was increased. X-ray diffraction shows that all cone arrays grow along the c-axis. Raman and photoluminescence spectra reveal that the optical properties of the buffer layer between the ZnO cone arrays and the silicon substrates are better than those of the ZnO cone arrays due to high concentration of Zn in the heads of the ZnO cone arrays and higher growth temperature of the buffer layer. The growth of ZnO arrays reveals that the cone arrays are synthesized through a self-catalyzed vapor-liquid-solid (VLS) process.     

Syntheses of CuO nanostructures in ionic liquids

A simple and efficient approach is developed to fabricate single-crystalline CuO nanostructures through an ionic liquid assisted one-step low-temperature solid-state route.Both nanoparticles(5 nm in size)and nanorods(5-10 nm in diameter and 50-100 nm in length)of monoclinic CuO were obtained. These synthesized CuO nanostructures were characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM),selected area electron diffraction(SAED),X-ray photoelectron spectros- copy(XPS),energy dispersive spectroscopy(EDS)and nitrogen adsorption analysis.The morpholo- gies of the nanostructures can be controlled by tuning the amount of NaOH and ionic liquids.The growth mechanism of CuO nanostructures is investigated.     

High-yield preparation of uniform cobalt hydroxide and oxide nanoplatelets and their characterization

Cobalt hydroxide nanoplatelets with a uniform hexagonal shape were prepared in high yield ( approximately 95%) by a facile hydrothermal route in the presence of poly(vinylpyrrolidone). This method provides a simple, low-cost, and large-scale route to produce beta-cobalt hydroxide nanoplatelets with an average diameter of 280 nm and a thickness of ca. 26 nm which show a predominant well-crystalline hexagonal brucite-like phase. Their thermal decomposition produced anisotropic nanoplatelets of cobalt oxides (CoO and Co3O4) under designed temperatures. The products were characterized by transmission electronic microscopy, selected-area electron diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetric, and thermogravimetric analysis. The magnetic properties of the products were investigated by a superconducting quantum interference device magnetometer. Co3O4 nanoplatelets exhibit a superparamagnetic behavior, and they might be a promising material to study the magnetic tunneling effect as anisotropic nanostructures.     

A template-free aqueous route to ZnO nanorod arrays with high optical property

A mild template-free aqueous route was successfully established to synthesize well-aligned ZnO nanorod arrays, which were proved to exhibit high optical property by PL spectra.     

Thickness-dependent photocatalytic performance of ZnO nanoplatelets

In this paper, we report the large-scale synthesis of ZnO nanoplatelets as thin as 10 nm. The nanoplatelets show higher efficiency in photodegrading organic dyes than ZnO nanorods do, and for the nanoplatelets, the thinner they are, the higher the performance. The photocatalytic decomposition of organic dyes (eosin B) by ZnO nanoplatelets compares favorably to the performances of ZnS porous nanoparticles and commercial Degussa P25 titania particles. This finding may have significant implications in the environment remediation and the fabrication of functional nanodevices.     

电化学聚合吡咯/噻吩导电共聚物纳米纤维阵列及其表征

导电聚合物因其具有良好的空气稳定性、电化学成膜性和导电性等特点,在二次电池、电色显示及固体电容器等方面都有诱人的应用前景.近年来人们研究导电聚合物的纳米结构时发现,由于超分子效应,纳米纤维中聚合物链会以平行于纤维轴向为优先取向,这种优先取向使导电聚合物纳米纤维的电导率比块材有极大提高.     

Direct-write,Well-aligned Chitosan-Poly(ethylene oxide) Nanofibers Deposited via Near-field Electrospinning

A continuous near-field electrospinning (NFES) process has been demonstrated to be able to achieve direct-write and well-aligned chitosan/poly(ethylene oxide) nanofibers. The ability to precisely control and deposit chitosan-based nanofibers in a direct-write manner is favorable in manipulating cells attachment and proliferation at a preferred position. Experimental results show that fiber diameters can be reliably controlled in the range of 265–1255 nm by adjusting various operating parameters of the NFES processes. These prescribed patterns of nanofibers exceed tens of centimeters long and complex configurations such as grid arrays and arc shapes are assembled at specified separations as small as 5 μm. FTIR analysis reveals that NFES nanofibers have a similar morphology and composition as conventional electrospinning counterpart and constitute all components formerly present in the polymer solution. The versatile functionality to fabricate chitosan-based nanofibers with controllable size and directional alignment as well as highly ordered and customized patterns may represent an ideal candidate of a functional biomaterial and in tissue-engineering scaffolds that are predominantly representative of extracellular matrix (ECM).     

Effect of Ultrasonic‐assisted Preparation Methods on Structure,Morphology and Optical Properties of Nanosized Cupric Oxide

Cupric oxide is a p‐type semiconductor with a narrow band‐gap which is suitable for catalysis, electrochemical cells, field emission devices and gas sensor applications. Despite considerable efforts devoted to the preparation of the nanosized CuO, there is a lack of information about ultrasonic‐assisted (US) preparation methods. Nanosized cupric oxide was successfully prepared through different ultrasonic‐assisted (US) preparation methods. Furthermore, the influence of preparation method on the structure, morphology and optical properties of nanosized CuO has been reported. XRD patterns were identical to the single‐phase pure CuO with a monoclinic structure. The enhancement of the crystallinity and crystallite size was observed for the sample prepared through the US thermal decomposition. The absorption band of CuO nanocrystals prepared through the US liquid hydrolysis shows a clear red shift of about 40 nm compared to those obtained with other preparation methods. Our results indicated that almost spherical CuO nanoparticles with an average size of 65 nm were prepared during the US thermal decomposition, while CuO rod‐like nanostructures with an average diameter of about 16 nm were obtained via the US liquid hydrolysis method. The band gap values of nanosized CuO samples were larger than the reported value for the bulk CuO. Synthesized CuO samples by US methods with adjustable and controllable properties make the applicability of cupric oxide even more versatile.