Hydrothermal Synthesis and Characterization of Quasi‐1‐D Tungsten Disulfide Nanocrystal

Quasi‐1‐D (one‐dimensional) tungsten disulfide (WS₂) nanocrystal was synthesized through a two‐step hydrothermal process. Energy dispersive spectroscopy (EDS) identified that the chemical composition of the final product was WS₂. The produced nanocrystal was further characterized with X‐ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The results have shown that most of the products are quasi‐1‐D nanocrystals with the width around 140 nanometers and thickness about 30 nanometers. However, the length of the majority of nanocrystals could reach 1 micron. The selected area electron diffraction (SAED) pattern indicates that the nanocrystal is of a single crystal. N₂ adsorption measurement revealed that the BET specific surface area of this sample is 97 m²g^?1, which indicates that the as‐prepared product has better catalyzing and friction performance.     

反应条件对ZnWO4纳米棒的形貌和光致发光性能的影响

采用水热法合成了ZnWO4纳米棒, 并用扫描电镜(SEM)、透射电镜(TEM)和粉末X射线衍射(XRD)等技术对产物进行了表征. 实验结果表明, 反应溶液的pH值和反应时间是影响ZnWO4纳米棒形成的重要因素. 研究了不同反应条件下制备的ZnWO4纳米晶的光致发光性能.     

Synthesis of oleylamine capped copper nanocrystals via thermal reduction of a new precursor

The present investigation reports the novel synthesis of copper nanocrystals using thermal reduction, and their physicochemical characterization. The copper nanocrystal powder has been prepared using [bis(2-hydroxyacetophenato)copper(II)] as a precursor. The effect of oleylamine and triphenylphosphine on the particle morphology has been investigated. Transmission electron microscopy (TEM) analysis has demonstrated that the copper nanocrystals have an average diameter of about 3 nm. The as-prepared copper nanocrystals were characterized by XRD, SEM, TEM, EDX, UV–Vis and FTIR.     

Characterizations and Photocatalytic Activities of Nanocrystalline MTiO3 （M = Sr, Pb, Co） Prepared via a General Self-propagating Combustion Method

Nanocrystalline MTiO3 (M=Sr, Pb, Co) were prepared by a general self-pro- pagating combustion method. The samples were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption and UV-vis diffuse reflectance spectra (DRS). The photocatalytic activity of MTiO3 (M=Sr, Pb, Co) was evaluated by the photocatalytic degradation of methyl orange (MO). MTiO3 (M=Sr, Pb, Co) having the same core element showed distinctly different photocatalytic activity due to the different coordinating atoms. Factors affecting the photocatalytic activity of MTiO3 (M=Sr, Pb, Co) were discussed. It was suggested that the structures of TiO6 octahedra and the electronic property were the predominant factors of the photocatalytic behavior for MTiO3 (M=Sr, Pb, Co).     

纳米晶簇多级孔道L沸石的合成及其脱硫性能

采用晶化培育法制备了L沸石纳米晶簇,以其作为前驱体,并以3-三甲基甲硅烷基丙基十六烷基二甲基氯化铵(TPHAC)为模板剂,合成了微孔-介孔多级孔道L沸石(MeLTL沸石).通过X射线衍射(XRD)、氮气吸附-脱附、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、27Al固体魔角核磁(27AlMASNMR)和吡啶傅立叶变换红外(Py-FTIR)等方法对MeLTL沸石进行了表征.研究结果表明,MeLTL沸石是由L沸石纳米晶簇自组装形成的,并具有介孔孔道和L沸石的微孔结构以及适宜的酸量与酸强度,其比表面积和孔体积分别高达611m2.g-1和0.696cm.3g-1.将MeLTL沸石作为添加剂引入柴油加氢脱硫催化剂载体中,并与添加L沸石、Al-MCM-41和仅以γ-Al2O3为载体的催化剂进行比较,其脱硫性能为最佳,经加氢后的柴油硫含量仅为9.3μg.g-1,脱硫率达99.3%.     

气-固相还原硫酸盐制备系列硫化物纳米晶

<正>过渡金属硫化物纳米晶因其特异的结构具有量子尺寸效应、小尺寸效应、表面效应等效应,显示出不同于体相材料的光电磁性质,因而成为近年来纳米科学研究的热点[1-3]。几十年来,硫化亚铁(FeS)     

溶剂热法合成锐钛矿型二氧化钛纳米晶的形状演化规律

以钛酸四丁酯为前驱体,乙醇为溶剂,月桂酸和十二胺为共同稳定剂,采用溶剂热法制备了不同形状的锐钛矿型二氧化钛纳米晶。利用透射电子显微镜(TEM)、选区电子衍射(SAED)、X射线衍射(XRD)、傅里叶变换红外(FTIR)光谱和热失重-差热分析(TG-DTA)等技术对纳米晶的结构、尺寸、形貌及形状进行了系统的表征,并探讨了月桂酸与十二胺不同配比时纳米晶的形状演化规律。结果表明:用溶剂热法在不同配比情况下获得的二氧化钛均为锐钛矿相;在月桂酸与十二胺总摩尔量不变的情况下,随着十二胺含量的增加,二氧化钛纳米晶的形状由球形逐渐演化为棒状,且结晶化程度在两者摩尔比为1:1时最好;月桂酸与十二胺稳定剂与纳米晶内核之间以桥接配位体的形式结合,且稳定剂在样品中的含量约为5%。     

溶胶-凝胶法制备聚醚砜-二氧化硅复合材料

以聚醚砜(PES)为基体,通过溶胶-凝胶过程,得到了分散均匀的PES/SiO₂杂化材料,用扫描电镜、透射电镜、傅里叶红外及差示扫描量热法研究不同SiO₂含量的PES/SiO₂杂化材料材料性能.结果表明,当PES/SiO₂杂化材料中SiO₂的质量分数大于10%时可获得有机聚合物链段与无机网络互穿的均匀分散的复合材料.此材料的玻璃化转变温度(Tg)明显提高.     

Cellulose nanocrystals obtained from microcrystalline cellulose by p-toluene sulfonic acid hydrolysis,NaOH and ethylenediamine treatment

Cellulose nanocrystals (CNCs) were first isolated from microcrystalline cellulose (MCC) by p-toluene sulfonic acid (p-TsOH) hydrolysis. Cellulose II nanocrystal (CNC II) and cellulose III nanocrystal (CNC III) were then formed by swelling the obtained cellulose I nanocrystal (CNC I) in concentrated sodium hydroxide solutions and ethylenediamine (EDA) respectively. The properties of CNC I, CNC II and CNC III were subjected to comprehensive characterization by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The results indicated that CNC I, CNC II and CNC III obtained in this research had high crystallinity index and good thermal stability. The degradation temperatures of the resulted CNC I, CNC II and CNC III were 300 °C, 275 °C and 242 °C, respectively. No ester bonds were found in the resulting CNCs. CNCs prepared in this research also had large aspect ratio and high negative zeta potential.

     

Self-assembly of PbTe quantum dots into nanocrystal superlattices and glassy films

Monodisperse lead telluride (PbTe) nanocrystals ranging from approximately 4 to 10 nm in diameter are synthesized to provide quantum dot building blocks for the design of novel materials for electronic applications. Two complementary synthetic approaches are developed that enable either (1) isolation of small quantities of nanocrystals of many different sizes or (2) the production of up to 10 g of a single nanocrystal size. PbTe nanocrystals are characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and optical absorption. Assembly of PbTe nanocrystals is directed to prepare nanocrystal solids that display either short-range (glassy solids) or long-range (superlattices) packing order by varying deposition conditions. Film order and average interparticle spacing are analyzed with grazing-incidence small-angle X-ray scattering (GISAXS) and high-resolution scanning electron microscopy (HRSEM). We perform the first optical and electronic studies of PbTe solids and demonstrate that chemical activation of these films enhances conductivity by approximately 9-10 orders of magnitude while preserving their quantum dot nature.     

Metal-cation-mediated nanocrystal arrays of sandwich-type (phthalocyaninato) [tetrakis(4-pyridyl)porphyrinato] cerium complex formed at the water-chloroform interface

Regular square, wirelike, quadrate, and rodlike nanocrystal arrays of Cd2+, Hg2+, or Ag+ metal-cation-mediated sandwich-type mixed (phthalocyaninato) [5,10,15,20-tetrakis(4-pyridyl)poprhyrinato] cerium(III) double-decker complex Ce(Pc)(TPyP) have been successfully prepared at the water-chloroform interface. The nanocrystal growth processes were monitored by transmission electron microscopy (TEM), which reveals that different morphologies of nanocrystals have been fabricated from double-decker molecules connected by different kinds of metal cations, forming coordination polymers. These nanoscaled coordination polymers were characterized by FT-IR spectra and energy-dispersive X-ray spectra (EDS). EDS results clearly revealed the elements of the nanocrystals and the FT-IR spectra give evidence for the coordination interaction between the double-decker molecules and metal cations. The UV-vis absorption spectrum indicates the formation of J-aggregates of the double-decker molecules in the nanocrystals formed.     

Preparation and Characterization of SiO2/Co and C/Co Nanocomposites as Fisher-Tropsch Catalysts for CO2 Hydrogenation

To fabricate high-density cobalt-based catalysts, we first synthesized SiO₂/C composites via a hydrothermal method and removed C and SiO₂ by two different methods, respectively. The as-prepared SiO₂ and C supports then reacted with cobalt acetylacetonate and N,N-dimethylformamide(DMF) under hydrothermal conditions to prepare SiO₂/Co and C/Co nanocomposite catalysts. The catalysts were characterized by X-ray diffraction(XRD), scanning electron microscope(SEM), transmission electron microscopy(TEM), inductively coupled plasma mass spectrometry(ICP), energy dispersive X-ray fluoresence spectrometer(EDX), and nitrogen adsorption. It was found that hexagonal cobalt nanocrystals were successfully integrated with the mesoporous silica or carbon nanotube supports. SEM and TEM results show that SiO₂/Co composites with a hollow/mesoporous sphere structure and C/Co composites with a tubular structure have been successfully synthesized. Both composite samples show superparamagnetism exhibiting an S-type hysteresis loop, which originated from the cobalt nanoparticles in the samples. Nitrogen adsorption/desorption curves suggest that the SiO₂ and C supports have well-developed pore structures and large specific surface areas, and the loading and good dispersity of cobalt nanoparticles on the supports were proven by ICP and EDX. Moreover, the samples exhibited good and stable catalytic activity, demonstrating that the two composites are suitable catalysts for Fischer-Tropsch CO₂ hydrogenation.     

Solvothermal Synthesis and Characterization of HgTe Nanoplatelets Using Mercury(Ⅰ) Source

Mercury telluride (HgTe) nanoplatelets were obtained via a facile solvothermal reaction of mercury(Ⅰ) chloride and tellurium powder in ethylenediamine (en). Mercury(Ⅰ) was first applied as the mercury sources to prepare nanocrystal HgTe; moreover, the proposed mechanism for the fabrication of the sample was discussed in detail. The HgTe nanoplatelets were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM),transmission electron microscopy (TEM), high-resolution transmission electron microscopy(HRTEM) and Fourier transform infrared spectroscopy (FT-IR). The absence of IR absorption may render the title nanocrystal useful as an IR transparent material in the region.     

Solvothermal Synthesis and Characterization of HgTe Nanoplatelets Using Mercury（I） Source

Mercury telluride （HgTe） nanoplatelets were obtained via a facile solvothermal reaction of mercury（I） chloride and tellurium powder in ethylenediamine （en）. Mercury（I） was first applied as the mercury sources to prepare nanocrystal HgTe; moreover, the proposed mechanism for the fabrication of the sample was discussed in detail. The HgTe nanoplatelets were characterized by powder X-ray diffraction （PXRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, high-resolution transmission electron microscopy （HRTEM） and Fourier transform infrared spectroscopy （FT-IR）. The absence of IR absorption may render the title nanocrystal useful as an IR transparent material in the region.     

溶剂热合成法制备(Zn,Hg)S微晶和薄膜

近年来，由于Ⅱ～Ⅵ族半导体纳米材料的特殊物理、化学性质及其在半导体、光学器件、激光二极管、IR探测器等方面的广泛应用，它们的制备和表征引起了人们越来越大的兴趣犤１～１１犦。现在（Zn，Hg）S微晶正被广泛而深入的研究和应用。例如：一种发蓝光的激光二极管已经设计成功，它包含一夹在两衬层间的活性层，无论是在衬层还是在活性层中都包含有（Zn，Hg）S犤５犦。Sugao也曾报道过一种以（Zn，Hg）S为基础的半导体激光器件犤６犦。Parkin曾用MCl２（M＝Zn，Cd，Hg）和Li２E（E＝O，S，Se，Te）混合热解法制备ME或MxM'yS…     

Sol-Gel Co-Electrospun LiNiO2 Hollow Nanofibers

Using a coaxial capillary spinneret electrospinning technique combined with the sol-gel method, the nickelic xerogel hollow nanofibers first were prepared and the polycrystalline LiNiO₂ hollow nanofibers were obtained after sintering. The obtained hollow nanofibers were about 500 nm to 4 µm in outer diameter, and were made up of 20 ～ 30 nm nanocrystals. The xerogel hollow nanofibers and those calcined at different temperatures were characterized by thermogravimetric (TG) analysis, Fourier transform infrared (FTIR) spectrum, x-ray diffractometry (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM).     

Effect of kinetics on morphology and mechanical properties of poly(allyl diglycol carbonate)-poly(urethane) interpenetrating polymer networks

Simultaneous interpenetrating polymer networks (SINs) of polyallyl diglycol carbonate (ADC) and polyurethane (PU) were prepared by differing modes of synthesis. The kinetics of the network formation of each constituent component was investigated by gel time studies and infra-red spectroscopy. The effect of different rates of network formation of each component on the morphology and mechanical properties were studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), stress-strain, and single edge notch tension. TEM and DMA studies showed a two-phase separated morphology. The extent of phase eparation was dependent on the relative rate of formation of component networks. Thus, simultaneous gelation of both networks showed a fine morphology and exhibited improved toughness over neat ADC resin.     

Facile synthesis of hollow Co3O4 microspheres and its use as a rapid responsive CL sensor of combustible gases

The hollow Co(3)O(4) microspheres (HCMs) were prepared by the carbonaceous templates, which did not need the surface pretreatment. The chemiluminescence (CL) and catalytic properties for CO oxidation over these hollow samples were evaluated. The samples were characterized by scanning electron microscopy (SEM), energy disperse spectra (EDS), transmission electron microscopy (TEM), selected area electron diffraction (ED), X-ray diffraction (XRD), temperature-programmed desorption (TPD) and N(2) adsorption. The influences of filter' band length, flow rate of gas, test temperature, and particle structure on CL intensities were mainly investigated. It was found that compared with the solid Co(3)O(4) particles (SCPs), HCMs had a stronger CL intensity, which was ascribed to its hollow structure; and that CL properties of the catalysts were well correlated with their reaction activities. Moreover, HCMs were used to fabricate a highly sensitive gas detector, which is a rapid and effective method for the selection of catalysts or the detection of environmental deleterious gases.     

十六烷基三甲基溴化铵插层α-磷酸锆复合物的合成、表征及其对酚的吸附机理

利用甲胺消弱α-磷酸锆(α-ZrP)层间作用力, 合成了不同十六烷基三甲基溴化铵(CTMAB)含量插层α-ZrP的复合物CTMAB-ZrP. 通过X射线粉末衍射(XRD), 傅里叶变换红外(FTIR)光谱, 透射电子显微镜(TEM), 扫描电子显微镜(SEM)及氮气等温吸附对CTMAB-ZrP进行了表征, 推测了CTMAB在磷酸锆层间的排列形式. CTMAB-ZrP吸附水中苯酚的实验结果表明, CTMAB-ZrP对苯酚的吸附量不仅与CTMAB的插入量和层内空间位阻有关, 还与溶液的pH值密切相关. 对苯酚、2-氯苯酚、2,4-二氯苯酚、对甲基苯酚及3,5-二甲基苯酚的吸附实验结果表明, CTMAB-ZrP对酚类化合物的吸附量与酚的疏水性成正相关, 而与酚类化合物的酸性无关. Henry型和Freundlich型吸附等温方程都能很好地拟合CTMAB-ZrP对苯酚、2-氯苯酚和2,4-二氯苯酚的吸附过程, 表明吸附主要是酚在插层复合物层间有机相中的分配作用所致.     

液相法制备取向ZnO纳米线阵列的场发射特性(英文)

采用水热合成工艺,在不同条件下制备了不同的一维取向ZnO纳米线阵列样品.用X射线衍射仪(XRD)、扫描电镜(SEM)及透射电镜(TEM)对样品的晶体结构和形貌等进行了表征,对样品的场发射特性进行了分析和比较,并用Fowler-Nordheim方程对影响ZnO纳米线场发射的因素进行了研究.结果表明,具有较低生长密度分布、较高的长径比和较尖锐生长端的ZnO纳米线阵列样品具有较好的场发射特性.