General Route to Synthesize Monodisperse Oxide (Hydroxide) Nanoparticles

Mono-dispersed oxide and hydroxide nanoparticles have been synthesized through the solvothermal process in alcohol-water mixtures. The products were characterized by powder x-ray diffraction (XRD) and scanning electron microscopy (SEM). Plate-like nanoparticles are obtained for Bi₂O_2.33, Fe₂O₃, and Cd(OH)₂, and spherical nanoparticles are obtained for SnO₂. The growth mechanism for the mono-dispersed nanoparticles has been preliminarily discussed.     

帽状铝纳米粒子的制备及表面等离子共振特性

金属纳米材料具有许多独特的物理和化学性质,其中一个重要的光学性质就是表面等离子共振,然而在大多数情况下,金属纳米粒子表面等离子共振所产生的吸收峰被限制在相对狭小的范围内,很难进行调谐。近年来,以电介质为核金属为壳的核壳结构复合纳米材料成功的解决了这一问题,通过设计和剪裁内核的直径与外壳层厚度的比值,可以实现光学性质可调的特性[1～5]。此类复合材料可被广泛应用于光催化、传感器、光信息存储、生物光子学、生物医学等领域[6～11]。美国莱斯大学及德州的研究人员利用这类核壳结构纳米材料成功地实现了对体外乳腺肿瘤的杀灭实验[12]。在这种类型的材料中,对称性降低的即不完全包裹的纳米粒子如杯状[13]、帽状[13,14]、半球壳状[15]、月牙状[16]等核壳结构复合粒子由     

SiO2 /Au核壳结构纳米粒子的制备及表征

通过以金纳米粒子为表面晶种和壳生长的方法制备了金纳米壳包覆二氧化硅的复合纳米粒子。采用TEM 和UV-Vis对复合粒子进行了表征和研究，结果表明所得到的复合粒子粒径均匀、金纳米壳光滑完整，且壳厚度可通过反应物的用量来控制。当核半径与壳厚度之比在4到13之间变化时,复合粒子的光学共振峰在可见光区到近红外光区范围内可发生大于500 nm波长的移动。     

简易合成Cu2SnSe3作染料敏化太阳能电池对电极

采用简易溶剂热法合成直径为150-250 nm的Cu2SnSe3纳米颗粒.以Cu2SnSe3"墨水"为前驱体采用滴落涂布法在掺氟二氧化锡基板上沉积Cu2SnSe3薄膜作为染料敏化太阳能电池(DSSC)对电极.利用场发射扫描电镜(FESEM)、透射电镜(TEM)、X射线衍射(XRD)、拉曼光谱(Raman)、能谱仪(EDS)等对Cu2SnSe3纳米颗粒的形貌、结构和组成进行表征.结果表明:产物纯净无杂项且符合化学计量比.以Cu2SnSe3为对电极的DSSC转化效率为7.75%,与铂对电极DSSC效率相当(7.21%).研究表明,DSSC的光电流密度和影响因子与Cu2SnSe3薄膜厚度密切相关,这是由于不同厚度的Cu2SnSe3薄膜作对电极所对应的催化位置数目和电阻值不同.电化学阻抗谱研究说明,Cu2SnSe3因具有类似铂良好的电催化性能而适合用作染料敏化太阳能电池对电极材料.本文以Cu2SnSe3代替贵金属铂,提供了一种廉价制备高效染料敏化太阳能电池对电极的新方法.     

表面Cu2O纳米颗粒修饰高效促进γ-Bi2MoO6的可见光催化活性

采用水热法在γ-Bi₂MoO₆光催化剂表面修饰了纳米级Cu₂O, 得到了具有高效可见光响应的复合光催化材料, 并利用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)、X射线光电子能谱(XPS)和紫外-可见漫反射光谱(UV-Vis-DRS)等技术对其相结构、微观形貌和光吸收性能进行了表征. 在可见光条件下(λ>400 nm)考察了Cu₂O表面修饰对γ-Bi₂MoO₆光催化降解亚甲基蓝(MB)性能的促进作用. 结果表明, 纳米级Cu₂O(~10 nm)颗粒均匀地修饰于γ-Bi₂MoO₆的表面, 使γ-Bi₂MoO₆的可见光吸收带发生明显红移, 且吸收强度大幅提高, 增强了复合材料光生电子-空穴对的分离效率, 从而使复合材料表现出较高的光催化活性. 当Cu₂O的表面修饰量为1.5%(w)时, 复合光催化剂降解MB的活性与纯γ-Bi₂MoO₆相比提高了6.4倍.     

A novel nonenzymatic hydrogen peroxide sensor based on MnO2/graphene oxide nanocomposite

A new electrocatalyst, MnO₂/graphene oxide hybrid nanostructure was successfully synthesized for the nonenzymatic detection of H₂O₂. The morphological characterization was examined by scanning electron microscopy and transmission electron microscopy. The MnO₂/graphene oxide based electrodes showed high electrochemical activity for the detection of H₂O₂ in alkaline medium. The nonenzymatic biosensors displayed good performance along with low working potential, high sensitivity, low detection limit, and long-term stability, which could be attributed to the high surface area of graphene oxide providing for the deposition of MnO₂ nanoparticles. These results demonstrate that this new nanocomposite with the high surface area and electrocatalytic activity offers great promise for new class of nanostructured electrode for nonenzymatic biosensor and energy conversion applications.     

ZnO/In2O3复合空心球的制备及其光电催化葡萄糖降解性能

通过葡萄糖协助的水热以及随后的退火处理两步法成功制备了系列ZnO/In₂O₃复合空心球. X射线衍射谱(XRD)表明, 经500 ℃退火制得的ZnO/In₂O₃复合空心球中ZnO以非晶态存在, 但是随着退火温度的提高, 其逐渐转变为纤锌矿结构. 场发射扫描电子显微镜(FE-SEM)和透射显微镜(TEM)结果表明, ZnO/In₂O₃复合材料具有空心球结构, 复合纳米颗粒之间结合紧密. 将ZnO/In₂O₃复合空心球组装成薄膜光电极, 研究了其光电催化降解葡萄糖的性能. 结果表明, 700 ℃退火处理的ZnO/In₂O₃复合空心球薄膜电极可产生最高的光致电流密度. 通过光致发光光谱(PL)发现, 与ZnO或In₂O₃空心球相比, ZnO/In₂O₃复合空心球的发光强度猝灭效果明显. 这是由于复合材料中晶界处产生的p-n结电场, 降低了光生电子-空穴对的复合几率, 从而使更多的光生电子可迁移到电极表面.     

TiO2-SnO2复合氧化物微球的低温水热一步法合成及紫外屏蔽性能

以硫酸钛、 四氯化锡和尿素为原料, 采用低温水热法一步合成了TiO2-SnO2复合氧化物. 采用X射线衍射(XRD), 扫描电子显微镜/能量色散X射线谱仪(SEM/EDAX)及紫外-可见光谱(UV-Vis)对产物的结构与性能进行表征分析, 考察了反应条件对产物晶体结构和形貌的影响. 结果表明, 在静止反应条件下Ti4+/Sn4+摩尔比为6~8时, 可以获得尺寸均一的金红石结构TiO2-SnO2复合氧化物微球, 其平均粒径为2 μm. 产物的紫外吸收性能优于同种方法制备的纯TiO2, SnO2及商品P25.     

阳极氧化法制备二氧化钛纳米管及其荧光性质

室温下采用电化学阳极氧化法在NaF、Na₂SO₄和H₂SO₄的混合溶液中用化学处理后的纯Ti片表面组装了一层结构高度有序的高密度TiO₂纳米管阵列。考察了几种主要的实验参数(阳极氧化电压、温度、电解液浓度)对TiO₂纳米管阵列形貌和尺寸的影响，探讨了二次阳极氧化对纳米管形貌的改善。对TiO₂纳米管阵列进行扫描电子显微镜(SEM)和荧光(PL)分析，探讨其生长机理。结果表明，孔径随阳极氧化电压的升高而变大，温度、电解液浓度影响反应过程中电流密度的大小；二次阳极氧化得到的纳米管的有序性有所改善，孔径大小更为均一，并且发现TiO₂纳米管的荧光具有量子效应。     

TiO_2纳米管阵列光电极的电化学阻抗及动力学特性分析

采用声电化学阳极氧化法,在无机溶剂(H3PO4+NaF水溶液)和有机溶剂(NH4F+水+乙二醇)体系电解液中加20V直流电压制得TiO2纳米管(TNT)阵列,其中无机溶剂样品(记为TNT-A)的管长为650nm,有机溶剂样品(记为TNT-E)的管长为2μm.基于X射线衍射(XRD)图谱、场发射扫描电子显微镜图(FESEM)、紫外-可见漫反射光谱(UV-VisDRS)的表征和电流-时间(I-t)曲线、Mott-Schottky图和电化学阻抗谱(EIS)的分析可知,在空气中经500℃煅烧后,TNT-E的吸光性能明显好于TNT-A的吸光性能.在紫外光((365±15)nm)辐照下,测得TNT-E的平均光电流密度与TNT-A的仅差0.05mA·cm-2,这是由于管长的增长增大了电荷转移电阻,并使得传质路径增长,增大了反应所需克服的势垒,降低了电极的反应速率,两者的电荷载流子密度分别为5.31×1020与9.86×1020cm-3.     

浸渍-分解法制备高可见光催化活性的Bi2O3/TiO2纳米管阵列

用浸渍-分解法将Bi₂O₃纳米颗粒沉积在TiO₂纳米管壁上, 制备了Bi₂O₃/TiO₂纳米管阵列. 用电感耦合等离子体发射光谱(ICP-AES)测定了Bi₂O₃/TiO₂ 纳米管阵列的化学组分, 利用X 射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)和紫外-可见(UV-Vis)吸收光谱表征了所制备的样品. 通过在可见光下(λ>400 nm)降解甲基橙(MO)水溶液来评价样品的光催化活性. 结果表明, Bi₂O₃纳米颗粒均匀地沉积在TiO₂纳米管中. Bi₂O₃/TiO₂纳米管阵列具有比纯Bi₂O₃膜和N-TiO₂纳米管阵列高得多的可见光催化活性. Bi₂O₃/TiO₂纳米管阵列活性的增强是其强可见光吸收和Bi₂O₃与TiO₂之间形成的异质结的协同作用的结果.     

Acoustical and thermodynamical parameters of aluminium oxide nanoparticles dispersed in aqueous ethylene glycol

In the present work aluminium oxide (Al₂O₃) nanoparticles were synthesised by the precipitation method using AlCl₃ as a starting material. The synthesised nanoparticles were characterised by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). These nanoparticles have been dispersed in base fluid, an aqueous solution of ethylene glycol (EG). Density (ρ), ultrasonic velocity (u), and viscosity (η) for these nanofluids have been measured at different concentrations as a function of temperature (T = 303.15 K, 308.15 K, and 313.15 K). Using their values various acoustical and thermodynamical parameters have been computed.     

Preparation of surface plasmon resonance biosensor based on magnetic core/shell Fe3O4/SiO2 and Fe3O4/Ag/SiO2 nanoparticles

In this paper, surface plasmon resonance biosensors based on magnetic core/shell Fe(3)O(4)/SiO(2) and Fe(3)O(4)/Ag/SiO(2) nanoparticles were developed for immunoassay. With Fe(3)O(4) and Fe(3)O(4)/Ag nanoparticles being used as seeding materials, Fe(3)O(4)/SiO(2) and Fe(3)O(4)/Ag/SiO(2) nanoparticles were formed by hydrolysis of tetraethyl orthosilicate. The aldehyde group functionalized magnetic nanoparticles provide organic functionality for bioconjugation. The products were characterized by scanning electronic microscopy (SEM), transmission electronic microscopy (TEM), FTIR and UV-vis absorption spectrometry. The magnetic nanoparticles possess the unique superparamagnetism property, exceptional optical properties and good compatibilities, and could be used as immobilization matrix for goat anti-rabbit IgG. The magnetic nanoparticles can be easily immobilized on the surface of SPR biosensor chip by a magnetic pillar. The effects of Fe(3)O(4)/SiO(2) and Fe(3)O(4)/Ag/SiO(2) nanoparticles on the sensitivity of SPR biosensors were also investigated. As a result, the SPR biosensors based on Fe(3)O(4)/SiO(2) nanoparticles and Fe(3)O(4)/Ag/SiO(2) nanoparticles exhibit a response for rabbit IgG in the concentration range of 1.25-20.00 μg ml(-1) and 0.30-20.00 μg ml(-1), respectively.     

光诱导富精氨酸多肽修饰的Fe2O3@Au纳米粒子的细胞毒性

以人宫颈癌细胞(HeLa细胞)为对象考察了富精氨酸多肽RRRRRRRR(R8)修饰的金-三氧化二铁壳核纳米粒子(R8-Fe2O3@Au NPs)对活细胞的光毒性. 研究结果表明, 内化后的R8-Fe2O3@Au NPs对活HeLa细胞无显著的细胞毒性, 但在激光照射下则可导致HeLa细胞的凋亡, 表现出很强的细胞光毒性. R8-Fe2O3@Au NPs的细胞光毒性与照射激光波长有关, 并随细胞吞噬的R8-Fe2O3@Au NPs的量、 光照强度和时间的增加而增强.     

Preparation and Characterization of CdTe Nanoparticles in Zirconia Films Prepared by the Sol Gel Method

Two methods for the synthesis of CdTe nanoparticles in zirconia sol-gel films are demonstrated. The nanoparticles were obtained by chemical reduction of Te(IV) using reducing agent (hydrazine) or tin chloride. Particle sizes ranging from 6 to 20 nm in diameter could be prepared by varying the experimetal parameters. The size and crystalline structure of the particles were characterized by optical absorption, X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. The film morphology was characterized by scanning force microscopy.The film obtained by SnCl₂ method is smooth and homogeneous. The dense structure of CdTe nanoparticles of a few nm in diameter is revealed. The films prepared with hydrazine are porous as a result of evolution of the decomposition gaseous products during the reduction.Advantages and disadvantages of the two methods are discussed.     

In2O3八面体的碳还原法制备及其发光性能研究

In₂O₃ octahedrons were synthesized by carbothermal reduction using In₂O₃ nanoparticles as the source material. The as-synthesized products were characterized by X-ray powder diffraction (XRD), energy dispersive X-ray(EDX), scanning electron microscopy(SEM), transmission electron microscopy(TEM), high-resolution transmission electron microscopy (HRTEM), selected-area electron diffraction analysis(SAED) and Room-temperature photoluminescence(PL) spectroscopy. The results show that the products are single-crystalline In₂O₃ octahedrons, the length of the octahedrons is in the range of 400～3 000 nm; the PL patterns display two peaks located at 447nm and 555 nm upon excitation at 380 nm, and the other two peaks located at 444 nm and 550 nm upon excitation at 325 nm; the excitation pattern shows two peaks located at 274 nm and 371 nm, respectively. The growth mechanism of the In₂O₃ octahedrons is discussed, and the high supersaturation ratio is considered as the key factor.     

锂离子电池负极材料ZnMn2O4微米空心球的制备和电化学性能

通过溶剂热方法合成了ZnMn2O4微米空心球,并探讨了其形成机理。采用XRD,SEM,TEM等测试手段对产物的结构、形貌和组成进行了表征。实验结果表明,溶剂热反应条件如反应温度、反应介质对于产物的结构和形貌起着关键作用。在140℃,采用乙醇和水作为反应介质,反应6 h可以制备出直径约3μm的ZnMn2O4微米空心球;当以乙醇为溶剂,反应6 h可以得到团聚的尺寸约250 nm的ZnMn2O4纳米颗粒。将所制备的ZnMn2O4微米空心球/纳米颗粒组装成锂扣式模拟电池,考察其电化学脱嵌锂性能。电化学测试结果显示,与ZnMn2O4纳米颗粒相比,空心结构的ZnMn2O4微米球具有较高的初始放电容量(1335 mAh·g-1)和较好的倍率性能,有望作为锂离子电池的新型负极材料。     

氧缺陷型SnO2纳米颗粒可见光催化性能的研究

由简单的水热法合成了一种可高效降解有机染料的氧缺陷型Sn O2纳米颗粒新型光催化剂,用X射线衍射、透射电镜、高分辨透射电镜和紫外-可见分光光度计等手段对其结构及性能进行了表征。结果表明,所制备的催化剂的禁带宽度最小可达2.90e V,可实现对可见光的有效吸收利用,对甲基橙的降解反应具有很高的光催化活性。将该催化剂(1g/L)分散在10mg/L的甲基橙溶液中,可见光照射下,40min内甲基橙的降解率达99%以上。由于该催化剂具有合成方法简单、高效、成本低和反应条件温和等特点,为有效解决有机染料对环境的污染问题提供了一条新的途径。     

Enhanced ethanol sensing properties of WO3 modified TiO2 nanorods

Pristine and WO₃ decorated TiO₂ nanorods (NRs) were synthesised to investigate n-n-type heterojunction gas sensing properties. TiO₂ NRs were fabricated via hydrothermal method on fluorine-doped tin oxide coated glass (FTO) substrates. Then, tungsten was sputtered on the TiO₂ NRs and thermally oxidised to obtain WO₃ nanoparticles. The heterostructure was characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectroscopy. Fabricated sensor devices were exposed to VOCs such as toluene, xylene, acetone and ethanol, and humidity at different operation temperatures. Experimental results demonstrated that the heterostructure has better sensor response toward ethanol at 200 °C. Enhanced sensing properties are attributed to the heterojunction formation by decorating TiO₂ NRs with WO₃.