熔盐法合成NiO纳米微晶

纳米科技的基础是纳米结构材料的合成．它是纳米科技在分散与包覆、高比表面材料、功能纳米器件、强化材料等方面实现突破的起点。纳米颗粒（1-100nm）本身具有宏观量子隧道效应、量子尺寸效应、表面效应许多独特的性能．其制备研究日益得到广泛关注和重视．     

亲油性ZnS纳米微粒的合成

纳米微粒具有小尺寸效应、表面效应、量子效应和宏观量子隧道效应等一系列普通材料所不具备的特性 ,因而引起科技工作者的广泛重视 ,成为材料科学研究的热点 .制备纳米微粒的方法很多 [1～ 7] ,但由于纳米微粒的小尺寸效应及表面效应 ,通常制备的无机纳米微粒极易团聚 ,而且无机纳米微粒的非油溶性使其在摩擦学领域的应用受到很大限制 .本文采用表面修饰 [8～ 11] 方法 ,通过共沉淀的竞争反应 ,制备了表面为有机修饰剂双十六烷基二硫代磷酸 (DDP)修饰的无机 Zn S纳米微粒 ,并用红外光谱、 X射线光电子能谱和透射电子显微镜等分析手段对表…     

不同取向的CoSb3纳米线阵列的电化学法制备

近年来,金属纳米线及其阵列由于其新奇的物理和化学特性和在纳米器件方面潜在的应用前景,越来越受到人们的关注。氧化铝模板合成一维纳米材料具有设备简单、制作方便等优点,因而成为近年来人们常用的一种方法。利用电化学沉积的方法在多孔氧化铝模板中沉积各种成分的纳米线已成为纳米材料制备的一种常见的方法。这种方法不仅可以得到大面积有序的纳米线阵列,还可以根据需要调节孔洞的大小来控制纳米线的直径[1￣3]。最近理论研究结果预言[4￣6],由于纳米材料的量子限域效应,热电材料的纳米线将有比其相应块体材料更高的品质因数n,这极大地激…     

纳米复合镀技术

纳米粒子具有的量子尺寸效应，表面效应和宏观量子隧道效应等，使其表现出很多独特的物理及化学性能，采用液相金属电沉积技术，通过将纳米粒子引入金属镀层中形成的纳米复合镀层，显示出优越的机械性能，电催化性能，耐腐蚀性能等，正逐渐成为研究的热点，本文介绍了纳米复合镀层的制造技术及纳米复合镀层的结构以及纳米复合镀层的研究现状。     

CdS纳米微粒在LB膜层隙聚集形态的AFM观察

用LB技术制备纳米微粒与超薄有机膜的复合膜是近年来值得注意的研究进展＊．利用该方法所制备出的材料既具有纳米粒子所特有的量子尺度效应，又具有LB股的分子层次有序、股厚可控以及易于组装等特点．它可用来制备结构可控的有机无机交替膜．而且，通过改变LB膜成膜材料和制备条件还可改变纳米粒子的光电特性．因此它在微电子学、光电子学、非线性光学及传感器等研究领域有着十分广阔的应用前景问．纳米微粒的聚集形态及LB膜在生成纳米微粒后的结构变化对材料的特性有着很大的影响．但采用一般的电镜技术或光谱分析手段均不能在实空间和…     

光电流谱、光致发光光谱和紫外可见吸收光谱在纳米半导体光电器件研究中的联用

在纳米半导体中由于纳米效应(如量子尺寸效应),其电子结构与块体半导体有所不同。进一步地,当纳米半导体与基底和其他组分结合制成器件后,其性质又受到基底或其他组分的影响,这两点导致了基于纳米半导体的光电器件的性能以及相应表征方法也大不相同。将光电流谱、光致发光光谱和紫外可见吸收光谱三种技术有机地结合起来,可以更好地表征纳米半导体的电子性质和光电性能。本文根据纳米半导体材料与电极的电子性质特点及其测量,结合本课题组前期工作,举例介绍三种谱学方法相结合应用于探究光伏电池和电致发光器件的纳米半导体材料的性能,以及纳米半导体材料表面态的表征。     

纳米CaCO3改性对医用胶乳制品的影响

纳米CaCO3是20世纪80年代发展起来的一种新型超细固体材料。由于纳米CaCO3的超细微化，其晶体结构和表面电子结构发生变化，产生普通碳酸钙所不具有的量子尺寸效应、小尺寸效应、表面效应和宏观量子效应。也由于纳米CaCO3的超细微化，使其自身存在难以克服的缺点——附聚形成二次结构。如果附聚粒子最终不能被碾碎后分散，就会潜伏下来，成为应力集中点，最终导致改性材料性能的下降，欲充分发挥纳米CaCO3的纳米效应，有必要研究其填充改性的影响因素，从而确立纳米CaCO3填充改性的最佳参数。实验证明：纳米CaCO3表面状态、含量、表面处理剂用量、纳米CaCO3表面活化改性时搅拌时间都对纳米CaCO3填充改性的效果产生影响。     

纳米氧化锌的微乳液法制备

纳米ZnO颗粒尺寸较小,比表面积较大,其粉体具有非常高的化学活性,表现出表面与界面效应、小尺寸效应、量子尺寸效应和宏观量子隧道效应.纳米ZnO在电、磁、光、热等方面具有一般ZnO所无法比拟的性能,广泛用于气体敏感材料、涂料和高效催化剂等许多领域.因而,制备高质量的纳米ZnO是非常重要的.     

CdTe/CdS共敏化TiO2电极材料的制备与光电性能

将电沉积法和化学浴沉积法结合,分别将CdTe和CdS量子点纳米晶材料引入到TiO_2纳米管阵列上制备CdTe/CdS量子点共敏化TiO_2光电极。利用扫描电镜、X射线衍射和X射线能量色散光谱等测试手段对所得样品的形貌、晶型和组分进行表征。在模拟太阳光照射条件下,通过电化学工作站测试其光电化学性能。研究结果表明,相对于单一量子点敏化CdS/TiO_2和CdTe/TiO_2光电极而言,共敏化CdTe/CdS/TiO_2光电极表现出更好的光电转化性能,短路电流密度和光电转换效率分别可以达到3.1 m A·cm~(-2)和1.85%。此外,采用电化学阻抗测试技术对材料性能提升的原因进行深入的探究。     

溶液体系中的纳米金属粒子形状控制合成*

纳米尺度的金属粒子由于量子尺寸效应等原因而表现出不同于宏观金属块体的电学、磁学、光学和热学等性质.纳米金属粒子的性质不仅受到尺寸的影响,还与粒子的形状密切相关.不同形状的纳米金属粒子通常具有不同的表面结构和性质.近年来,纳米金属粒子的形状控制合成正受到越来越多的关注;其中,Ⅷ族和IB族金属的研究已取得一定进展.本文评述了纳米金属粒子的合成以及尺寸和形状控制的方法,分别介绍了铂、钯、镍、金、银、铜以及钴等金属的形状控制合成的近期研究进展.     

Top-down synthesized TiO2 nanowires as a solid matrix for surface-assisted laser desorption/ionization time-of-flight (SALDI-TOF) mass spectrometry

Top-down synthesized TiO₂ nanowires are presented as an ideal solid matrix to analyze small biomolecules at a m/z of less than 500. The TiO₂ nanowires were synthesized as arrays using a modified hydrothermal process directly on the surface of a Ti plate. Finally, the feasibility of the TiO₂ nanowires in the anatase phase as a solid matrix. The crystal and electronic structures of the top-down TiO₂ nanowires were analyzed at each step of the hydrothermal process, and the optimal TiO₂ nanowires were identified by checking their performance toward the ionization of analytes in surface-assisted laser desorption/ionization time-of-flight (SALDI-TOF) mass spectrometry. Finally, the feasibility of the TiO₂ nanowires in the anatase phase as a solid matrix for SALDI-TOF mass spectrometry was demonstrated using eight types of amino acids and peptides as model analytes.     

钛基TiO2纳米管阵列电极的光电催化性能

应用电化学阳极氧化法在纯Ti基底上制备高度有序的TiO2纳米管阵列,考察了Ti/TiO2光阳极的光电化学响应.以苯酚溶液为目标污染物,研究Ti/TiO2电极的光电催化性能,并与光催化性能进行比较.结果表明,该电极光电催化性能优于光催化性能.施加0.6 V电压时,光电催化性能最好.电化学阻抗谱分析显示,光电催化和光催化降解过程的速控步骤均为表面反应步骤,外加偏压减小了界面电荷转移阻抗,提高了光生载流子的分离效率.     

Synthesis and Photochemical Properties of Monolithic TiO2 Nanowires Diode

In this paper, the structural and photochemical properties of a monolithic photochemical diode are discussed. The present structure is composed, from the top to the bottom, of a TiO₂ nanowire layer, a TiO₂ film, a Ti foil, and a porous layer made of Pt nanoparticles. The synthesis of the nanowires was simply carried out by Au-catalysed-assisted process; the effects of the annealing temperature and time were deeply investigated. Morphological and structural characterizations were performed by scanning electron microscopy and Raman spectroscopy. The analyses showed the rutile structure of the TiO₂ nanowires. The photocatalytic properties were studied through the degradation of methylene blue (MB) dye under UV light irradiation. The nanowires induced an enhancement of the photo-degradation rate, compared to TiO₂ in a bulk form, due to an increase in the surface area. Moreover, the presence of a nano-porous Pt layer deposited on the rear side of the samples provided a further increase in the MB degradation rate, related to the scavenging effect of Pt nanoparticles. The overall increment of the photo-activity, due to the nano-structuration of the TiO₂ and to the presence of the Pt layer, resulted a factor 7, compared to the bulk reference. In addition, photovoltage measurements allowed to assess the effects of TiO₂ nano-structuration and Pt nanoparticles on the electron accumulation.     

Syntheses of TiO2(B) nanowires and TiO2 anatase nanowires by hydrothermal and post-heat treatments

TiO₂(B) nanowires and TiO₂ anatase nanowires were synthesized by the hydrothermal processing in 10 M NaOH aq. at 150 °C followed by the post-heat treatment at 300-800 °C. As-synthesized Na-free titanate nanowires (prepared by the hydrothermal treatment and repeated ion exchanging by HCl (aq.) were transformed into TiO₂(B) structure with maintaining 1-D morphology at 300-500 °C, and further transformed into anatase structure at 600-800 °C with keeping 1-D shape. At 900 °C, they transformed into rod-shaped rutile grains. Microstructure of these 1-D TiO₂ nanomaterials is reported.     

Addition of TiO2 nanowires in different polymorphs for dye-sensitized solar cells

TiO₂ (B) and TiO₂ anatase nanowires were prepared at 150 °C for 120 h by a hydrothermal method followed by calcination in air at 400 °C for 2 h and at 700 °C for 2 h for TiO₂ (B) and TiO₂ anatase, respectively. Although dye-sensitized solar cells (DSC) with fully nanowire electrodes showed a rather low light-to-electricity conversion efficiency of 1.33 % for TiO₂ (B) and 2.42% for TiO₂ anatase, 10 wt % nanowire-dispersed electrodes in a P-25 TiO₂-nanoparticle matrix demonstrated improved efficiency of 6.17 % for TiO₂ (B) and 6.53% for TiO₂ anatase, these exceeding that of pure P-25 electrodes in this work (η=5.59%). The dominant mechanisms of the improvement at 10 wt% for the two different polymorphs are thought to be different, i.e., a light-scattering and film-thickness increment for the TiO₂ (B) system, whereas there is an improved conduction path through the matrix for the TiO₂ anatase system.      

Synthesis of immobilized TiO2 nanowires by anodic oxidation and their gas phase photocatalytic properties

In this paper, anodic oxidation method was successfully employed to the direct growth of immobilized TiO₂ nanowires on titanium foil in ethylene glycol electrolyte solution contained HF and water. The morphologies of the TiO₂ nanowires could be tuned by changing the content of HF and water. The structures, morphologies and optical properties of TiO₂ nanowires were characterized by SEM, XRD, UV–vis and PL. It was found that the nanowires originally grew from the splitting of TiO₂ nanotubes. The gas phase photocatalytic activities were investigated by photodegradation of gaseous toluene under UV irradiation, and irregular TiO₂ nanowires showed the best photocatalytic ability.     

低温静电自组装法制备贵金属修饰TiO_2纳米结构薄膜及其增强的光催化性能(英文)

以碱-水热法在金属Ti片上原位生长了TiO2纳米结构(纳米花和纳米线)薄膜,并采用低温静电自组装方法将超细贵金属(金、铂、钯)纳米颗粒均匀沉积于多孔TiO2薄膜上.负载于Ti片上的贵金属/TiO2纳米结构薄膜具有一体化结构、多孔架构和高光催化活性.超高分辨率场发射扫描电子显微镜(FESEM)直接观察表明贵金属纳米颗粒在TiO2表面分布均匀,且颗粒之间相互分离,金、铂、钯纳米颗粒的平均粒径分别约为4.0、2.0和10.0nm.俄歇电子能谱(AES)纵深成分分析表明贵金属不仅沉积于薄膜表面,且大量分布于TiO2纳米结构薄膜内部,其深度超过580 nm.X射线光电子能谱(XPS)分析表明,经300°C下在空气中热处理后,纳米金仍保持金属态,纳米铂部分被氧化成PtOabs,而钯粒子则完全被氧化成氧化钯(PdO).以低温静电自组装法沉积贵金属,贵金属负载量可通过调节组装时间与溶胶pH值来控制.光催化降解甲基橙的结果表明,沉积的纳米金和铂能显著增加TiO2纳米结构薄膜的光催化活性,说明金和铂粒子可促进光生载流子的分离;但负载的PdO对TiO2薄膜的光催化性能增强几乎无作用.     

The evolvement of pits and dislocations on TiO2-B nanowires via oriented attachment growth

TiO₂-B nanowires were synthesized by an ion exchanging-thermal treatment. The unique morphology of pits and dislocations interspersed on TiO₂-B nanowires were firstly characterized and studied by high-resolution transmission electron microscopy (HRTEM). Oriented attachment is suggested as an important growth mechanism in the evolvement of pits and dislocations on TiO₂-B nanowires. Lattice shears and fractures were originally formed during the ion exchanging process of the sodium titanate nanowires, which resulted in the formation of primary crystalline units and vacancies in the layered hydrogen titanate nanowires. Then the (110) lattice planes of TiO₂-B grown in [110] direction is faster than the other lattice planes, which caused the exhibition of long dislocations on TiO₂-B nanowires. The enlargement of the vacancies, which was caused by the rearrangement of primary crystalline units, should be the reason of the formation of pits. Additionally, the transformation from TiO₂-B to anatase could be also elucidated by oriented attachment mechanism.     

阴离子改性甘油溶液中TiO2纳米管阵列的制备和表征

本文采用电化学阳极氧化法以含氟的甘油和水混合溶液为电解液在纯钛表面制备了一层排列规整的TiO2纳米管阵列,研究了电解液中额外添加3种2价阴离子、不同的电解时间及不同的添加物浓度等因素对所获得的TiO2纳米管阵列形貌的影响。结果表明,在改性电解液中制备的TiO2纳米管阵列的长度均超过了未改性的电解液中制备的,并随着氧化时间的增长,纳米管管口直径增大,管壁变薄;同时添加的(NH4)2TiF6浓度在0.025~0.1 mol.L-1范围内均可获得管长更长且形貌较好的TiO2纳米管阵列。     

水热法制备TiO_2纳米线薄膜的光生阴极保护性能

应用水热法在钛箔表面制备TiO2纳米线薄膜,采用场发射扫描电子显微镜、X射线衍射和紫外-可见分光光度法对薄膜进行表征,用电极电位和电化学阻抗谱考察TiO2光生阴极保护性能.结果表明:薄膜由纵横交错的锐钛矿型TiO2纳米线组成,纳米线的直径约10nm.在150℃下反应6h生成的TiO2纳米线薄膜在0.3mol·L-1 Na2SO4溶液和0.3mol·L-1 Na2SO4+0.5mol·L-1 HCOOH混合溶液中对与TiO2薄膜耦连的403不锈钢均有良好的阴极保护效应.TiO2膜所在溶液中含有HCOOH时,可使耦连的403不锈钢在0.5mol·L-1 NaCl溶液中电极电位负移约545mV,界面反应电阻显著变小,表明电解质溶液加入HCOOH可以增强TiO2纳米线薄膜对403不锈钢的光生阴极保护效应.