水热法生长方式对ZnO纳米棒阵列结构和性能的影响

本文系统地比较了三种方式制备的ZnO纳米棒阵列的结构和性能的异同.根据水热法生长液中碱来源的不同,ZnO纳米棒阵列的生长方式分为三种:N方式(氨水)、H方式(六次甲基四胺)和NH方式(两次N方式和一次H方式).通过扫描电子显微镜,对这三种方式生长的ZnO纳米棒阵列形貌进行了表征.此外,利用X射线衍射仪、透射电子显微镜和激光拉曼光谱对ZnO的结晶性能进行比较.结果表明,ZnO纳米棒阵列的取向性N≈NH>H,ZnO的晶体质量H>NH>N.NH方式综合N方式和H方式的优势,得到了取向性和晶体质量优良的ZnO纳米棒阵列.这将为在进一步应用中有效地选择ZnO纳米棒阵列的制备方式提供重要信息.     

微/纳米ZnO粉体在Glu-BF_4离子液体水溶液中的诱导生长

以一定浓度谷氨酸-氟硼酸(Glu-BF_4)离子液体水溶液为反应介质,摩尔比为1∶6的二水合醋酸锌和氢氧化钠为反应物,在室温下制备前驱体,再通过微波辅助加热制备了具有绒球形貌的微/纳米ZnO粉体.利用扫描电子显微镜(SEM)、X射线衍射仪、比表面积测试仪、能谱仪、拉曼光谱仪和透射电子显微镜(TEM)等对产物形貌、晶型、比表面积、组成和晶面分布进行了测定.结果显示,所得产物为六方晶系纤锌矿结构,平均粒径20.4 nm,绒球大小1.6~3.0μm,比表面积为28.3 m~2/g,产物纯度较高.当反应物浓度一定,离子液体浓度分别为0.02,0.04,0.08和0.12 mol/L时都得到了类似形貌的微/纳米ZnO粉体,且随着离子液体使用量的增加,绒球尺寸分布更加均一.当离子液体浓度一定,而反应物浓度逐渐下降时,产物形貌发生递变性变化.ZnO晶粒在Glu-BF_4离子液体诱导下首先生成不规则的纳米片,纳米片进一步聚集,在一定反应物浓度范围内生成绒球形貌粉体,反应物浓度较低时只生成绒球的核心部分,而浓度更高时则生成纳米针阵列.通过不同条件下纳米ZnO粉体形貌变化规律,探讨了强碱性条件下Glu-BF_4离子液体水溶液中微/纳米ZnO粉体的生长机制.     

离子液体辅助水热法合成六方WO3纳米棒束

提出了利用简单的离子液体1-甲基-3-乙基-咪唑溴辅助水热法合成六方WO₃纳米棒束的方法,对其结构进行了表征,并讨论其形成机理。TEM照片表明：WO₃纳米棒束由长200~300 nm、直径25~30 nm的纳米棒组装而成。离子液体1-甲基-3-乙基-咪唑溴在纳米棒的形成过程中起到了结构导向剂的作用。     

离子液体辅助水热法合成六方WO3纳米棒束

提出了利用简单的离子液体1-甲基-3-乙基-咪唑溴辅助水热法合成六方WO₃纳米棒束的方法,对其结构进行了表征,并讨论其形成机理。TEM照片表明:WO₃纳米棒束由长200~300nm、直径25~30nm的纳米棒组装而成。离子液体1-甲基-3-乙基-咪唑溴在纳米棒的形成过程中起到了结构导向剂的作用。     

CdS量子点敏化ZnO纳米棒阵列电极的制备和光电化学性能

采用连续式离子层吸附与反应法制备了CdS量子点敏化的ZnO纳米棒电极.应用扫描电子显微镜(SEM)、X射线衍射(XRD)和透射电子显微镜(TEM)对CdS量子点/ZnO纳米棒电极的形貌、晶型和颗粒尺寸进行了分析和表征;采用光电流-电位曲线和光电流谱研究了不同CdS循环沉积次数及不同沉积浓度对复合电极的光电性能影响.结果表明,前驱体浓度都为0.1mol·L-1且沉积15次敏化后的ZnO纳米棒阵列电极光电性能最好.与单纯的ZnO纳米棒阵列电极和单纯的CdS量子点电极相比,其光电转换效率显著提高,单色光光子-电流转换效率(IPCE)在380nm处达到76%.这是因为CdS量子点可以拓宽光的吸收到可见光区,并且在所形成的界面上光生载流子更容易分离.荧光光谱实验进一步说明了光电增强的原因是,两者间形成的界面中表面态大大减少,有利于减少光生电子和空穴的复合.     

常温直接沉淀法制备ZnO纳米棒

在常温下, 以PEG-400(聚乙二醇400)为表面活性剂, 采用直接沉淀法合成了ZnO纳米棒. 产物用XRD, TEM, SAED和 HRTEM等进行了表征. 结果表明, 所得ZnO为一维的纳米棒, 属于六方纤维矿的单晶结构. ZnO纳米棒的直径在20~40 nm之间, 长度在300~800 nm范围. (0001)面为ZnO纳米棒的生长方向. 讨论了ZnO相的生成和ZnO纳米棒的形成机理以及PEG-400在其形成过程中的作用.     

电沉积种子层化学控制生长氧化锌纳米棒和纳米管

采用水溶液法在电沉积的ZnO种子层上制备了高度取向的ZnO纳米棒阵列,并通过碱溶液化学腐蚀法获得了ZnO纳米管。对ZnO纳米棒和纳米管的溶液生长和腐蚀过程进行了分析。结果表明,种子层的结构和性能对ZnO纳米棒有着重要的影响,在-700 mV电位下沉积的种子层薄膜均匀性好,生长的纳米棒密度大、与基底垂直性好;碱溶液对纳米棒的腐蚀具有选择性,通过控制腐蚀液的浓度和时间,可获得中空的ZnO纳米管。     

离子液体中不同形貌ZnO纳米材料的合成及表征

在不同的咪唑基离子液体中通过微波加热合成出了ZnO的片状聚集体、棒状聚集体和塔棒聚集体等纳/微米结构, 考察了不同合成条件对ZnO形貌的影响, XRD表明产物为六方相纤锌矿ZnO结构, SEM和TEM表明产物形貌主要分为片的聚集体和棒的聚集体, 电子衍射表明ZnO棒具有单晶结构, 片的聚集体的PL谱表明在室温下这种形貌的ZnO具有很强的绿光发射和弱紫外光发射现象.     

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.     

咪唑类离子液体辅助水热法合成棒状微/纳米ZnO晶体

以醋酸锌和氢氧化钠为原料, 以水和含不同长度烷基链的咪唑类氯盐离子液体的混合物作为反应介质, 采用水热法合成出不同形貌的微/纳米ZnO晶体, 用扫描电子显微镜(SEM)和X射线衍射仪(XRD)对合成的ZnO晶体进行表征. 研究了烷基链长度、 离子液体用量、 反应时间以及反应温度对形成棒状ZnO晶体形貌的影响. 实验结果表明, 所制备的棒状ZnO晶体样品均为六方晶系结构. 在棒状ZnO晶体的制备过程中, 控制反应温度, 选择不同的离子液体及其用量十分重要.     

Ionic liquid-assisted synthesis of silver nanorods by polyol reduction

<正>Silver nanorods have been successfully synthesized in large scale by the ethylene glycol(EG) reduction in the presence of ionic liquid(IL) 1-butyl-3-methylimidazolium tetrafluoroborate(bmimBF_4) and polyvinyl-pyrrolidone(PVP).The silver nanorods were characterized by scanning electron microscopy(SEM),high-resolution transmission electron microscopy(HRTEM),transmission electron microscopy(TEM),electron energy disperse spectroscopy(EDS) and UV-vis spectroscopy.The results showed that the uniform silver nanorods have an average diameter of about 100 nm and the aspect ratio from 15 to 20.IL,bmimBF_4 may play a role of capping agent together with PVP in the formation of silver nanorods.On the other band,bmimBF_4 may accelerate nucleation and improve the stability of the resulting Ag nanorods due to the low interface tension of IL.     

均匀沉淀法制备氧化锌纳米棒

采用均匀沉淀法制备了氧化锌纳米棒,用XRD,TEM,PL等检测手段对样品进行了表征.结果表明:所得样品为长约100 nm,宽约30 nm的纤锌矿结构氧化锌纳米棒,颗粒分布均匀.其在可见光区比紫外区的荧光发射显著增强.     

Microwave-assisted synthesis of sulfide M2S3 (m = Bi, Sb) nanorods using an ionic liquid

Single-crystalline Bi(2)S(3) and Sb(2)S(3) nanorods have been successfully synthesized by the microwave-assisted ionic liquid method. The starting reagents were Bi(2)O(3) or Sb(2)O(3), HCl, Na(2)S(2)O(3), and ethylene glycol (EG) or ethanolamine, and the ionic liquid used was 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF(4)]). Our experiments showed that the ionic liquid played an important role in the morphology of M(2)S(3) (M = Bi, Sb). Single-crystalline Bi(2)S(3) nanorods could be prepared in the presence of [BMIM][BF(4)]. However, urchinlike Bi(2)S(3) structures consisting of nanorods were formed without using [BMIM][BF(4)]. Single-crystalline Sb(2)S(3) nanorods were obtained in the presence of [BMIM][BF(4)]. However, single-crystalline Sb(2)S(3) nanosheets could be prepared in the absence of [BMIM][BF(4)]. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and electron diffraction (ED).     

离子液体[Bmim]BF4中单分散Ru纳米粒子的制备及选择加氢性能

采用化学还原法在离子液体1-丁基-3-甲基咪唑四氟硼酸盐([BMim]BF₄)中制备了单分散纳米金属Ru粒子。采用X射线衍射(XRD)、透射电镜(TEM)、傅里叶红外光谱(FTTR)及热重(TG)对所制备样品的形貌和结构进行了表征。XRD表征结果显示：在[BMim]BF₄中制备的Ru具有六方紧密堆积结构,无氧化物峰出现;TEM结果显示：采用正滴法制备的Ru纳米粒子为球形颗粒,呈现良好的单分散状态,粒径分布窄,为2~5 nm,而采用反滴法制备的Ru纳米粒子则发生了严重的团聚,团聚体粒径大于10 nm;FTIR表征表明：Ru纳米粒子表面存在[BMim]BF₄液体层,分析二者之间存在较强的物理吸附作用,[BMim]BF₄在Ru纳米粒子的制备中起到了修饰剂和保护剂的双重作用,这一推论通过TG分析得到了进一步验证。将分散于[BMim]BF₄的Ru纳米粒子作为催化剂应用于苯选择加氢反应,结果分析表明：Ru-离子液体-苯反应体系中,苯转化率仅有0.3%;Ru-离子液体-苯-水反应体系中加氢活性较高,但环己烯选择性较低,在一定条件下,加氢30 min,苯转化率为27.3%,环己烯选择性仅为14.5%。     

Synthesis of Well-Dispersed NiO Nanoparticles with a Room Temperature Ionic Liquid

NiO nanoparticles have been prepared in a room temperature ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF₄). The morphology and microstructures of the NiO nanoparticles were investigated by transmission electron microscopy (TEM) and x-ray diffraction (XRD). The TEM micrographs indicated that the nanoparticles are uniform hexagons and well-dispersed. From the XRD patterns, the nanoparticles could be identified as cubic phase. In the reaction, bmimBF₄ is likely to act as a stabilizer and as a template, controlling the dispersion and morphology of the product.     

Synthesis of single-crystal gold nanosheets of large size in ionic liquids

Large-size single-crystal gold nanosheets have been successfully prepared by microwave heating of HAuCl(4) in ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate, without any additional template agent. Transmission electron microscopy (TEM), electron diffraction (ED), scanning electron microscopy (SEM), and X-ray powder diffraction (XRD) were used to characterize the resultant gold nanosheets. It was demonstrated that the ionic liquid could act as template agent for the formation of gold nanosheets. The present synthesis route is very simple and fast. It can be expected that the method can be extended to the fabrication of other metal nanosheets in ionic liquids.     

Mutual solubility measurements and correlations of imidazolium-based ionic liquid mixtures with alcohols

The mutual solubility of ionic liquids (ILs), 1-butyl-3-ethylimidazolium tetrafluoroborate, 1-butyl-3-propylimidazolium tetrafluoroborate, and 1,3-dibutylimidazolium tetrafluoroborate with alcohols, 1-propanol, 1-butanol, 1-pentanol, and 1-hexanol were measured at atmospheric pressure. Upper critical solution temperatures (UCSTs) were estimated from experimental results using a polynomial equation. The UCSTs increased as increasing the chain length of alcohol. On other hand, the decreasing UCSTs occurred when the alkyl chain length on the cation of ionic liquids increased. The (liquid + liquid) equilibrium data were correlated by the original UNIQUAC, extended UNIQUAC, and modified UNIQUAC models. The temperature dependence of the solubility of ILs in alcohols and alcohols in ILs is represented successfully using the UNIQUAC, extended UNIQUAC, and modified UNIQUAC models with a quadratic function of temperature for binary energy parameters.     

微波固相合成氧化锌纳米棒

通过前驱体的微波固相热分解法快速合成了氧化锌纳米棒, 其直径在60～385 nm之间, 长可达数微米. 前驱体则通过一步室温固相反应制备. 用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、能量色散X射线分析(EDX)和透射电子显微镜(TEM)对产物的结构和形貌进行了表征. 同时, 对氧化锌纳米棒的光致发光(PL)性能作了测试, 结果表明在355 nm处有一个明显的近带隙发射峰. 另外, 对比实验表明, 微波辐射在氧化锌纳米棒的形成过程中起了关键性作用, 并对其形成机理进行了初步探讨.     

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.     

在离子液/水体系中超声合成MoO_3纳米棒及其表征(英文)

采用超声波的方法在离子液(1-丁基-3-甲基氯代咪唑盐离子液,[BMIM]Cl)中合成了直径分布在80~150 nm的MoO3纳米棒.采用X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、场发射扫描电子显微镜(FESEM)、高分辨透射电子显微镜(HRTEM)和选区电子衍射(SAED)对所合成材料的微观结构和形貌进行了表征.此外,考察了反应时间、加入[BMIM]Cl的量以及其它咪唑基离子液对产物的影响并提出了可能的反应机理.最后对在不同温度煅烧下所得的α-MoO的甲烷催化燃烧活性进行了表征.