两种一维纳米结构钒氧化物的合成与表征

在水热条件下，分别利用十六胺和十六烷基三甲基溴化铵为模板，合成了两种一维纳米结构的钒氧化物：纳米管和纳米棒，采用XRD、TEM、HRTEM、FT-IR、TG/DTA对产物的形貌和结构进行了表征。研究表明，纳米管的长度主要分布在1～10 μm，外径50～100 nm，内径10～30 nm；纳米棒长1～2 μm，径向尺寸50～200 nm。     

Ni(OH)2纳米管的制备、表征及电化学性能

以多孔氧化铝为模板, 在不同溶液浓度下, 用化学沉积法制备了氢氧化镍纳米管. 采用XRD, SEM, TEM和HRTEM等手段, 对产物的物相、表面形貌及微结构进行了表征. 结果表明所得产物是高纯度的氢氧化镍纳米管, 外径约为180～220 nm, 管壁厚20～30 nm. 将所制备的氢氧化镍纳米管制成电极, 其电化学性能测试表明, Ni(OH)₂纳米管的中空结构特点, 能够有效地提高镍电极的充电效率、放电比容量、高倍率及高温放电性能. 机理分析表明中空结构的Ni(OH)₂纳米管对于提高碱性二次电池的综合性能有着极为重要的意义.     

Ni(OH)2纳米管的制备、表征及电化学性能

以多孔氧化铝为模板, 在不同溶液浓度下, 用化学沉积法制备了氢氧化镍纳米管. 采用XRD, SEM, TEM和HRTEM等手段, 对产物的物相、表面形貌及微结构进行了表征. 结果表明所得产物是高纯度的氢氧化镍纳米管, 外径约为180～220 nm, 管壁厚20～30 nm. 将所制备的氢氧化镍纳米管制成电极, 其电化学性能测试表明, Ni(OH)₂纳米管的中空结构特点, 能够有效地提高镍电极的充电效率、放电比容量、高倍率及高温放电性能. 机理分析表明中空结构的Ni(OH)₂纳米管对于提高碱性二次电池的综合性能有着极为重要的意义.     

一步化学溶液法合成ZnO纳米管

以Zn(Ac)₂和NaOH为原料,采用一步化学溶液法,通过同时添加两种表面活性剂十二烷基苯磺酸钠(SDBS)和十二烷基硫酸钠(SDS),制备出形貌规则、结晶良好的一维ZnO纳米管。用X-射线衍射(XRD)、扫描电镜(SEM)、高分辨透射电镜(HRTEM)、选区电子衍射(SAED)和荧光光谱(PL)分别对产品的结构、形貌和发光性质进行了表征。结果表明,ZnO纳米管为沿c轴方向择优生长的六方晶型纤锌矿结构,管外径为720～780 nm,管壁厚约120 nm,平均长度为1.5 μm,在紫外和可见光区有不同程度的荧光发射。本文初步探讨了ZnO纳米管的形成机理,研究了表面活性剂、溶液碱度等对生成产物的影响。     

染料掺杂聚吡咯微纳米管的合成及其影响因素研究

以水溶性染料酸性红G为掺杂剂, 以三氯化铁为氧化剂, 采用无模板自组装方法制备得到了聚吡咯微/纳米管. 利用FTIR, XRD, SEM, TEM对所合成的聚吡咯微/纳米管的结构形貌进行了表征. 结果表明, 搅拌条件下, 酸性红G原位掺杂得到的聚吡咯管直径在100～910 nm之间, 管长大于50 μm. XRD表明所得聚吡咯微/纳米管为无定形态. 研究了反应时间、反应温度、吡咯浓度、掺杂剂与吡咯浓度比、氧化剂滴加速度等对聚吡咯管形貌的影响, 获得了最佳的反应条件.     

制备均一形貌的长二氧化钛纳米管

在温和的水热条件下，用碱溶液处理不同粒径的锐钛矿相和金红石相二氧化钛 纳米粉体，得到了不同形貌的二氧化钛纳米管，并用TEM，XRD，FT-Raman和BET等 对其进行了表征。金红石相的超细纳米晶有利于形成均一形貌的纳米管，用粒径仅 为7.2 nm的金红石相纳米粉体为前驱体得到了长度为500 nm的长二氧化钛纳米管。 用纳米晶反应活性对晶粒尺寸的依赖性及晶相稳定性解释了长纳米管的形成机理。     

水热法合成Bi2S3纳米管及其生长机理

以硝酸铋[Bi(NO)3]和硫化钠(Na2S)为反应原料, 采用水热法在120 ℃下反应12 h, 制备出Bi2S3纳米管. 利用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、选区电子衍射(SAED)和高分辨透射电镜(HRTEM)对其结构和形貌进行了表征. 结果表明, 所制备的产物是结晶良好的正交相Bi2S3纳米管, 其外径为100~500 nm, 内径为50~200 nm, 长为1~5 μm. 根据实验结果讨论了Bi2S3纳米管的生长机理. 初步研究了反应温度和矿化剂种类对产物形貌和结构的影响.     

纳米管状结构立方萤石型CeO2的合成(英)

低温水热条件下，Ce⁴⁺离子经尿素水解均匀沉淀，在十八胺分子模板导向下形成了多层有序排列的纳米管状结构的立方萤石型CeO₂，采用粉末X射线衍射(PXRD)、透射电镜(TEM)、高分辨透射电镜(HRTEM)以及选区电子衍射(SEAD)等手段对产物进行了表征。结果表明，该结构是由单根外、内径分别为10～20 nm、5～6 nm左右的纳米管有序排列形成的纳米管束构成，且产物具有结晶性良好的立方萤石型CeO₂晶体结构。在管束的生长过程中，反应体系首先形成单根纳米管，继而管与管之间又相互缔合生长成多层有序排列的纳米管束。控制尿素的水解，获得了不同pH值下的反应产物，发现反应体系pH值在5～6之间时产物为立方萤石型CeO₂、6～8时为立方萤石型CeO₂与六方型Ce(OH)CO₃的混合物、大于8则为六方型Ce(OH)CO₃。     

二氧化钛纳米管阵列薄膜的超声辐射阳极氧化制备

通过使用铂片作为对电极在含有氢氟酸的二甲基亚砜溶液中, 将金属钛片进行阳极氧化的方法制备得到二氧化钛纳米管阵列薄膜. 在施加40 V偏压超声辐射作用下阳极氧化24 h条件下得到的二氧化钛纳米管长达到680 nm, 管内直径25 nm, 管壁厚度约3～5 nm. 采用了XRD和TEM等分析手段表征了二氧化钛纳米管阵列薄膜的微观结构和表面形貌, 分别测试了薄膜的光吸收性能、循环伏安特性和光化学转换效率, 并和碱性溶胶-凝胶方法制备的纳米晶二氧化钛薄膜作了对比研究. 实验制备的二氧化钛纳米管阵列薄膜电极的光吸收率比纳米晶二氧化钛薄膜提高了40%, 光电化学转换效率前者是后者的6倍, 实验结果表明二氧化钛纳米管阵列薄膜结构有利于加快电子的传输, 并能减少电荷复合, 采用这种二氧化钛纳米管阵列薄膜结构的染料敏化太阳能电池光电极有望进一步提高太阳能电池的效率. 本文还探讨了在超声波辐射作用下二氧化钛纳米管阵列薄膜的形成机理.     

SiO2纳米管的合成及表面功能修饰研究

在氨水的负催化作用下, 用酒石酸氢铵作模板剂, 原硅酸四乙酯(TEOS)经水解、缩聚, 生成SiO₂纳米管. 利用硅烷偶联剂KH-570对SiO₂纳米管进行表面修饰, 将乙烯基(-CH＝CH₂)引入SiO₂纳米管表面, 改善其表面功能性. 通过扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)和傅立叶红外(FT-IR)等分析测试手段研究了SiO₂纳米管的形貌结构及其表面修饰性能. 结果表明: 溶液的pH值是影响SiO₂纳米管形貌的最主要因素, 最合适的酸碱度是4.5≤pH≤5.0; 纳米管平均外径300 nm, 内径100 nm, 长度10 µm以上, 管径均匀, 管壁表面光滑平坦, 没有出现裂纹等缺陷, 为无定形结构. KH-570功能修饰前后的纳米管形貌没有发生任何变化.     

Synthesis of Eu2O3 nanotube arrays through a facile sol-gel template approach

Eu2O3 nanotubes have been successfully fabricated by an improved sol-gel template method within the nanochannels of porous anodic alumina templates. The morphology, structure, and composition of the nanotubes were characterized by means of X-ray diffraction techniques, scanning electron microscope, transmission electron microscopy, and selected-area electron diffraction. The results show that the Eu2O3 nanotubes are polycrystalline with a cubic structure. The outer diameter of nanotubes is 50-80 nm, and the thickness of the tube wall is about 5 nm. The mechanism of nanotube formation was discussed.     

阳极氧化铝模板上热扩散法制备MoOx纳米阵列

采用简单的热扩散法, MoO3可在模板纳米孔道内有序生长, 经还原后获得MoO2和金属Mo纳米管／线阵列. 运用XRD、SEM、TEM、HRTEM等技术对产物进行了表征. 结果表明: 在70 nm孔径的阳极氧化铝模板上, H2/N2气氛下600 ℃时的还原产物为单晶MoO2; 而在50 nm的模板上, 同样条件的还原产物为MoO2微晶聚合体. 乙醇的加入能够大大改善产物的形貌. H2气氛, 650 ℃以上温度下进一步还原得到了金属Mo纳米管阵列.     

Protein nanotubes comprised of an alternate layer-by-layer assembly using a polycation as an electrostatic glue

We present the synthesis and structure of various protein nanotubes comprised of an alternate layer-by-layer (LbL) assembly using a polycation as an electrostatic glue. The nanotubes were fabricated by sequential LbL depositions of positively charged polycations and negatively charged proteins into a porous polycarbonate (PC) membrane, followed by release of the cylindrical core by quick dissolution of the template with CH(2)Cl(2). This procedure provides a variety of protein nanotubes without interlayer cross-linking. The three-cycle depositions of poly-L-arginine (PLA) and human serum albumin (HSA, M(w)=66.5 kDa) into the porous PC template (pore diameter, D(p)=400 nm) yielded well-defined (PLA/HSA)(3) nanotubes with an outer diameter of 419+/-29 nm and a wall thickness of 46+/-8 nm, revealed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations. The outer diameter of the tubules can be controlled by the pore size of the template (200-800 nm), whereas the wall thickness is always constant, independent of the D(p) value. The (PEI/HSA)(3) (PEI: polyethylenimine) nanotubes showed a slightly thin wall of 39+/-5 nm. CD spectra of the multilayered (PEI/HSA)(n) film on a flat quartz plate suggested that the secondary structure of HSA between the polycations was almost the same as that in aqueous solution. The three-cycle LbL depositions of PLA and ferritin (M(w)=460 kDa) or myoglobin (Mb, M(w)=1.7 kDa) into the porous PC membrane also gave cylindrical hollow structures. The wall thickness of the (PLA/ferritin)(3) and (PLA/Mb)(3) nanotubes were 55+/-5 nm and 31+/-4 nm; it depends on the globular size of the protein (ferritin>HSA>Mb). The individual ferritin molecule was clearly seen in the tubular walls by SEM and TEM measurements.     

Novel ice structures in carbon nanopores: pressure enhancement effect of confinement

We report experimental results on the structure and melting behavior of ice confined in multi-walled carbon nanotubes and ordered mesoporous carbon CMK-3, which is the carbon replica of a SBA-15 silica template. The silica template has cylindrical mesopores with micropores connecting the walls of neighboring mesopores. The structure of the carbon replica material CMK-3 consists of carbon rods connected by smaller side-branches, with quasi-cylindrical mesopores of average pore size 4.9 nm and micropores of 0.6 nm. Neutron diffraction and differential scanning calorimetry have been used to determine the structure of the confined ice and the solid-liquid transition temperature. The results are compared with the behavior of water in multi-walled carbon nanotubes of inner diameters of 2.4 nm and 4 nm studied by the same methods. For D(2)O in CMK-3 we find evidence of the existence of nanocrystals of cubic ice and ice IX; the diffraction results also suggest the presence of ice VIII, although this is less conclusive. We find evidence of cubic ice in the case of the carbon nanotubes. For bulk water these crystal forms only occur at temperatures below 170 K in the case of cubic ice, and at pressures of hundreds or thousands of MPa in the case of ice VIII and IX. These phases appear to be stabilized by the confinement.     

Sol–gel template synthesis and characterization of VO2 nanotube arrays

In this paper, we report on the obtention of highly ordered VO₂ nanotube arrays synthesized by the simple sol?Cgel template method. Techniques of transmission electron microscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy were used to characterize the morphology and structure of the as-synthesized nanotube arrays. It is found that the size of the as-obtained nanotubes has the dimension of 180?C220?nm in outer diameter, 110?C140?nm in inner diameter and up to 10???m in length. The results show that as-synthesized sample is assigned to VO₂ (B) phase in expected V/O ratio with V existing in the +4 oxidation state.     

Growth and surface properties of boehmite nanofibers and nanotubes at low temperatures using a hydrothermal synthesis route

The growth of boehmite nanostructures at low temperature using a soft chemistry route with and without (PEO) surfactant is presented. Remarkably long boehmite 1D nanotubes/nanofibers were formed within a significantly short time by changing the reaction mechanism of aluminum hydroxide. By using the PEO surfactant as a templating agent, boehmite nanotubes up to 170 nm in length with internal and external diameters of 2-5 and 3-7 nm, respectively, were formed at 100 degrees C. A slightly higher temperature (120 degrees C) resulted in the formation of lath-like nanofibers with an average length of 250 nm. Using the cationic surfactant CTAB, nanotubes rather than nanofibers were formed at 120 degrees C. Without surfactant, nanotubes counted for around 20% of the entire sample. A regular interval supply of fresh boehmite precipitate resulted in a larger crystallite size distribution of nanotubes. The morphology of nanotubes was more uniform in samples without the regular addition of aluminum hydroxide. Moreover, for the same hydrothermal time, the final nanotubes for nanomaterials without a regular interval supply of fresh aluminum hydroxide precipitate were longer than those with a regular aluminum hydroxide precipitate supply, which is in contrast to previously published results. Higher Al/PEO concentrations resulted in the formation of shorter nanotubes. A detailed characterization and mechanism are presented.     

纳米尺度电极材料的模板法合成及其电化学性能研究(英文)

本文利用氧化铝模板法合成了不同纳米尺寸的LiMn2 O4 纳米管 /纳米线及碳纳米管 .采用原子力显微镜 (AFM )及高分辨透射电镜 (TEM )表征了相关的模板及纳米管 .同时也报道了以纳米管阵列的LiMn2 O4 电极的循环伏安法的初步研究结果     

Synthesis of vanadium oxide nanotubes via an ultrasonic method

Vanadium oxide nanotubes were synthesized using V₂O₅ powder as the precursor and hexadecylamine as the structure-directing template using a sol-gel reaction method followed by a one-step hydrothermal treatment. The effect of ultrasonics on the formation of nanotubes is reported. The structure and morphology of the nanotubes were investigated by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The inner and outer diameters of the nanotubes varied from 20 to 40 nm and 80 to 100 nm, respectively. The nanotubes measured several micrometers in length.     

磁电CoFe2O4/BaTiO3纳米管的溶胶-凝胶模板法合成和表征

用溶胶-凝胶模板法合成了 CoFe2O4)/BaTiO3(CFO/BTO)复合纳米管,管的直径约为 100、200 和 300 nm,其长度约为100 μm.x射线衍射(xRD)和选区电子衍射(sAED)都显示复合纳米管中同时存在尖晶石相的CoFe2O4(CFO)和钙钛矿相的 BaTiO3(BTO),进一步的透射电子显微镜(TEM)研究证实合成的纳米复合物具有明显的管状结构.磁、电研究表明,该复合纳米管的磁性与纯 CFO 纳米管的磁性相当;而铁电性与纯BTO纳米管的铁电性相当.     

多级结构ZSM-5沸石分子筛的合成及其Mo基催化剂在甲烷无氧脱氢芳构化中的应用

以经盐酸预处理的碳纳米管为第二模板,在不添加其它有机溶剂的情况下,仅通过控制晶化条件,即采用变温水热晶化法合成具有多级结构的ZSM-5分子筛.通过x射线衍射、红外光谱测试、透射电镜和N2吸附对合成的分子筛进行了表征,结果表明,该合成分子筛呈近球形,是由纳米棒自组装形成的具有多级结构的亚微米球.该分子筛改性后用于甲烷无氧脱氢芳构化反应,显示出良好的催化性能,甲烷转化率最初达到19%,反应至24 h时甲烷转化率仍保持在10%左右,并且保持了较高的芳香物选择性(达到50%以上).