水溶性银纳米颗粒的制备及抗菌性能

采用液相还原法, 以单宁酸为还原剂, 聚乙烯吡咯烷酮(PVP)为修饰剂制备出了水溶性的表面修饰Ag纳米颗粒. 通过X 射线粉末衍射仪(XRD)、透射电子显微镜(TEM)、紫外-可见吸收分光光度计(UV-Vis)、傅里叶变换红外(FTIR)光谱仪等对所得样品的形貌和结构进行了表征. 采用肉汤稀释法测试了样品的抗菌性能, 考察了样品在水相中的分散稳定性, 提出了PVP修饰Ag纳米颗粒的形成机理. 结果表明所制备的样品具有Ag的面心立方晶体结构, 平均粒径为15-17 nm. 样品在水相中能长时间稳定分散; 对埃希氏大肠杆菌(E. coli)、金黄色葡萄球菌(S. aureus)具有明显的抗菌作用. 操作简便、条件温和的制备方法易于在工业规模上放大; 试剂无毒, 使得所制备的PVP修饰Ag纳米颗粒作为抗菌剂具有良好的应用前景.     

功能化离子液体中Ag纳米微粒的制备及摩擦学性能研究

合成了1-甲基-3-羟乙基咪唑四氟硼酸盐离子液体([C₂OHmim]BF₄)，用红外光谱表征了其结构。以所合成的离子液体作为还原剂、稳定剂与反应介质制备了Ag纳米微粒，用XRD和TEM对微粒的结构和形貌进行了表征。在四球摩擦磨损实验机上研究了[C₂OHmim]BF₄离子液体及掺入Ag纳米微粒后的离子液体的摩擦学性能。掺入银纳米微粒后，离子液体在高载荷下的润滑性有了大幅的改善。用SEM和XPS分别对磨痕表面的形貌和元素组成、化学状态进行了分析，结果表明：在低、高载荷分别起润滑作用的是有机膜和金属-有机复合膜。     

以Ag为模板制备Pt纳米空球及其对甲醇氧化的电催化性能

以硝酸银为前驱体,聚乙烯吡咯烷酮(PVP)为表面活性剂,抗坏血酸(AA)为还原剂,在18℃下通过调节氢氧化钠的加入量合成了2种不同粒径的银溶胶;以银溶胶为模板,在室温下合成了不同粒径的铂包银(Ag@Pt)实心纳米粒子;用浓氨水除去Ag核得到球壳上含残留银的铂纳米空球[(Pt-Ag)hollow]及其修饰玻碳(GC)电极[(Pt-Ag)hollow/GC];再用电化学法除去(Pt-Ag)hollow/GC电极上的残留银后,制得铂纳米空球(Pthollow)修饰的GC电极(Pthollow/GC).采用扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)、能量色散谱仪(EDS)和X射线衍射仪(XRD)等表征了Pthollow的形貌、组成和结构;以甲醇为探针分子,研究比较了Pthollow/GC和实心铂纳米粒子(Ptnano)修饰GC电极(Ptnano/GC)对甲醇氧化的电催化活性.结果表明,Pthollow分散性好,粒径比较均匀;球壳多孔,具有粗糙的内外表面,比表面积大,是由铂原子和多维多级的铂原子团簇构建的结晶度不高的多晶铂;Pthollow/GC对甲醇的电催化氧化活性明显优于Ptnano/GC电极,且大大降低了贵金属Pt的用量.     

氯化胆碱离子液体中纳米银的电化学制备与表征

在氯化胆碱离子液体中,采用牺牲阳极法直接从金属银制备了纳米银微粒;利用X射线衍射仪、透射电子显微镜、傅立叶红外光谱和热分析仪对样品进行了分析表征.结果表明:所制备的银纳米微粒大致呈球形,具有面心立方结构,粒径约为60nm.作为溶剂的离子液体同时具有分散剂和稳定剂的功能,可防止银纳米微粒之间的团聚及表面氧化.     

稳定分散的纳米银溶胶的制备及其表征

Stable aqueous dispersive colloidal Ag nanoparticles were prepared by reducing silver nitrate with sodium borohydride in the presence of 3-mercaptopropionic acid. The formation process of the Ag nanoparticles was investigated by UV-Visible spectroscopy and transmission electron microscopy. The results show that the spherical and rodlike particles and aggregates are formed in the initial stage of the reaction， then the rodlike particles and aggregates are gradually decomposed into small spherical particles， and the final obtained Ag nanoparticles with an average size of 8 nm are in uniform shapes and narrow size distribution， and the colloid remains stable for more than one month， which makes it convenient for use in practice. The presence of capping agent plays an extra role over nanoparticles stabilization and morphology. The presence of capping agent on the surface of Ag nanoparticle is confirmed by the X-ray photoelectron spectroscopy. It is found that Ag nanoparticles are negatively charged in alkaline condition， whereas they are positively charged in acid condition. Electrosteric effect is responsible for their long-term stability.     

载Ag二氧化钛纳米管的制备及其光催化性能

Titania nanotubes (TNTs) were synthesized by hydrothermal treatment of rutile-phase TiO2 nanoparticles in 10 mol·L-1NaOHsolution at 110 ℃ for 24 h. The Ag loaded titania nanotubes (Ag/TNTs) were obtained by chemical deposition method with the TNTs suspending in the AgNO3 solution (pH=8) at 50 益. The characterizations of the as-synthesized samples were performed by TEM, EDS, XRD, XPS, and UV-Vis spectra. The photocatalytic performance of the Ag/TNTs was investigated by UV-light induced photocatalytic decomposition of methyl orange(MO). The results showed that the inner/outer diameters of TNTs were about 6/10 nm and the length was several hundred nanometers. Both the shape and the crystalline of the nanotubes were not changed after the modification. The zero oxidation state Ag quantumdots, about 4 nmin diameter, were well dispersed on the external surface of the nanotubes. Ag/TNTs exhibited enhanced absorption at the visible range in the UV-Vis spectra. The Ag nanoparticles were found to significantly enhance the photocatalytic activity of TiO2 nanotubes, and the catalyst system was demonstrated to be highly efficient for the UV-light induced photocatalytic decomposition of MO compared to both rutile-phase TiO2 nanoparticles and pure TNTs. After irradiation for 60 min, the decomposition rates of MO solution in rutile-phase TiO2 nanoparticles, TNTs, and Ag/TNTs systemwere 46.8%, 57.2%, and 92.2%, respectively.     

聚多巴胺球支撑银纳米粒子制备无酶过氧化氢生物传感器

近年来,以聚多巴胺球支撑的纳米复合材料越来越受到人们的关注。聚多巴胺球有表面功能化基团如—OH、—NH_2等,决定了聚多巴胺球可以充当多种纳米复合材料的活性载体。利用聚多巴胺良好的还原性制备并负载银纳米粒子于聚多巴胺球表面,制备出的新型复合材料银纳米粒子-聚多巴胺球(以下简写为Ag@pdop)。Au修饰电极和银纳米粒子对过氧化氢的还原反应均具有很好的催化性能,利用两者特点将其复合制备修饰电极实现对H2O2的无酶传感,检测灵敏度达到了14.7μA/(mmol·L-1),检出限可达11.8μmol/L,线性范围0.2~6.0mmol/L,检测结果及抗干扰能力均令人满意。     

低代端酯基PAMAM树形分子存在下银纳米颗粒的制备

在低代端酯基PAMAM树形分子(G1.5-COOCH₃)存在时，用氢气还原AgNO₃制备出银纳米颗粒。用透射电子显微镜(TEM)，电子衍射(ED)，紫外-可见吸收光谱(UV-Vis)和红外光谱(FT-IR)对所制备的银纳米颗粒进行了表征。实验结果表明，当用氢气作为还原剂时，以低代树形分子为保护剂，通过优化还原条件，可成功制备尺寸稳定、均一的银纳米颗粒，其粒径为2.9±0.5 nm，且所制备的银纳米颗粒的粒径分布较窄。根据树形分子的理论尺寸与制备的银纳米颗粒的粒径关系，可推断出大多数的银纳米颗粒是由多个树形分子所包围而稳定存在。     

Preparation of Silica Microspheres Containing Ag Nanoparticles

Two sol-gel fabrication processes were investigated to make silica spheres containing Ag nanoparticles: (1) a modified Stöber method for silica spheres below 1 m size, and (2) a SiO₂-film formation method on spheres of 3–;7 m size. The spheres were designed to incorporate silver nanoparticles of high ⁽³⁾ in a spherical optical cavity structure for the resonance effect. For the incorporation, interaction between [Ag(NH₃)₂]⁺ ion and Si-OH was important. In the Stöber method, the size of the silica spheres was determined by a charge balance of plus and minus ions on the silica surface. In the film formation method, the capture of Ag complex ion on the silica surface depended on whether the surface was covered with OH groups or not. After doping [Ag(NH₃)₂]⁺ into silica particles or SiO₂ films on the spheres, these ions w ere reduced by NaBH₄ to form silver nanoparticles. From plasma absorption at around 420 nm wavelength and TEM photographs of nanometer-sized silver particles, their formation inside the spherical cavity structures was confirmed.     

ZnO/Ag复合纳米粒子的制备与表征

以乙酸锌为前驱物,乙醇为溶剂,油酸钠为表面修饰剂,采用溶液化学法,在乙醇体系中制得纳米Zn O。然后缓慢加入一定量的硝酸银乙醇溶液,在乙醇的还原作用下将Ag+还原为Ag纳米粒子,制得Zn O/Ag复合纳米粒子。通过紫外-可见吸收光谱(UV-Vis)、荧光光谱(FL)、透射电子显微镜(TEM)和X射线衍射(XRD)等方法对所制备的氧化锌-银复合纳米粒子样品进行表征。结果表明,所合成的Zn O/Ag复合纳米粒子为球形,尺寸为20-30nm且粒径分布较窄。Ag纳米粒子附着于Zn O纳米粒子表面,并起到良好的表面修饰作用。对制备Zn O/Ag复合纳米粒子的机理进行了初步探究。     

相转移方法制备银纳米粒子单层膜

在油酸钠保护下用NaBH_4还原AgNO_3，制得了银纳料粒子胶体溶液。利用相转 移剂NaH_2PO_4等，使Ag纳料粒子在水／朋机相界面之间形成薄膜。形成的Ag纳料 粒子膜可以转移到玻璃等基质上，讨论了其转移机理；并用石英晶体微天平（QCM ）宣检测了银纳料粒子的相转移量。     

铁表面银纳米粒子自组装膜及其缓蚀性能研究

应用化学还原法于水溶液中制备银纳米粒子.在十二烷基硫醇的保护下,将银纳米粒子从水相转移到甲苯相,并将处理好的铁电极浸泡在含有十二烷基硫醇保护的银纳米粒子/甲苯溶液中,制得十二烷基硫醇/银纳米粒子自组装混合膜.电化学方法如交流阻抗谱(EIS)、极化曲线等研究该自组装膜在0.5 mol.L-1H2SO4溶液中的缓蚀作用.XPS测试证实该自组装膜十二烷基硫醇和银纳米粒子之存在.     

羟基功能化离子液体中Ag纳米材料的制备及结构表征

Ag nanoparticles were prepared using hydroxyl-functionalized ionic liquids as reductant and reaction medium. Nanoparticles with different particle sizes were obtained by using ionic liquids with different structures, while nanorods were harvested when the reaction temperature was increased. The materials obtained were investigated by XRD and TEM. The results indicate that the crystal is in face-centred cubic structure for both of Ag nanoparticles and nanorods, and the diameter of Ag nanoparticles prepared in 1-ethoxyl-3-methyl imidazolium tetrafluoroborate ([C₂OHmim]BF₄), 1-(4′-hydroxyl)butyl-3-methyl imidazolium tetrafluoroborate ([C₄OHmim]BF₄) and 1-(6′-hydroxyl)hexyl-3-methyl imidazolium tetrafluoroborate ([C₆OHmim]BF₄) ionic liquid is about 25, 15 and 10 nm, respectively. And the diameter of Ag nanorods is about 200 nm and 2 μm in length. Finally, the formation mechanism of Ag nanoparticles and nanorods is proposed.     

Au/Ag核一壳结构复合纳米粒子形成机制的研究

在已制备好的Au纳米粒子表面,通过化学还原的方法沉积生长Ag包覆层,通过 控制Au, Ag的比列,制备了粒度均匀且粒径可控的Au/Ag核-壳结构纳米粒子。利用 UV-vis吸收光谱和透射电子显微镜（TEM）对SAu, Ag摩尔比为1：10的复合纳米粒 子的光学性质和形态进行随时监测,直接观察了核-壳结构纳米粒子的生长过程： 一部分Ag+在Au核表面还原生长,溶液中其余Ag+还原形成银的纳米团簇向粒子表面 的继续沉积生长,壳层增厚。     

Photogeneration of Silver Nanoparticle Facilitated by Pluronic F127 Surfactant in Ethanolic Solution

In the present study, the photo-generation of silver nanoparticles in ethanolic solution and in the presence of F127 block copolymer using UV irradiation have been investigated. The aim of the present study is preparing the green, facile and much faster method than previous studies. The kinetics of silver nanoparticles formation has been investigated by using UV-vis spectroscopy. The two-dimensioanl map technique has been used to estimate the switching time between the nucleation and growth of Ag nanoparticles. The results show that the dispersed Ag nanoparticle in ethanol can be formed by high intensity ultraviolet exposure within few minutes.     

吸附相反应技术制备Ag纳米粒子的反应机理

利用吸附相反应技术在SiO2表面制备Ag粒子, 研究了温度变化对载体表面NaOH的吸附、生成Ag的反应过程以及产物Ag粒子形貌的影响. NaOH的吸附率测定结果表明, 吸附平衡时间随着温度升高而增加. 温度升高加快了NaOH与Si—O—Si的反应, 使得NaOH的平衡吸附率不随吸附层的破坏而减少. 采用实时在线UV-Vis光谱研究了Ag粒子的生成过程, 发现温度超过40 ℃时, 反应体系中Ag出现的时间、Ag粒子的浓度和粒径分布范围都发生较大变化. 样品的TEM和XRD分析也表明, 当体系温度超过40 ℃时SiO2表面Ag粒子出现了团聚, 其晶粒粒径也出现了突变. 温度升高导致表面吸附层破坏, 使得Ag的生成场所从吸附层转移到SiO2表面, 最终导致Ag的反应机理和粒子形貌的变化.     

Ag Nanocomposite Particles: Preparation,Characterization and Application

Summary Herein, we report that different core-shell particles could be successfully used as the carrier systems for the deposition of silver nanoparticles. Firstly, thermosensitive core-shell microgel particles have been used as the carrier system for the deposition of Ag nanoparticles, in which the core consists of poly (styrene) (PS) whereas the shell consists of poly (N-isopropylacrylamide) (PNIPA) network cross-linked by N, N′-methylenebisacrylamide (BIS). Immersed in water the shell of these particles is swollen. Heating the suspension above 32 °C leads to a volume transition within the shell, which is followed by a marked shrinking of the network of the shell. Secondly, “nano-tree” type polymer brush can be used as “nanoreactor” for the generation of silver nanoparticles also. This kind of carrier particles consists of a solid core of PS onto which bottlebrush chains synthesized by the macromonomer poly (ethylene glycol) methacrylate (PEGMA) are affixed by “grafting from” technique. Thirdly, silver nanoparticles can be in-situ immobilized onto polystyrene (PS) core-polyacrylic acid (PAA) polyelectrolyte brush particles by UV irradiation. Monodisperse Ag nanoparticles with diameter of 8.5 nm, 7.5 nm and 3 nm can be deposited into thermosensitive microgels, “nano-tree” type polymer brushes and polyelectrolyte brush particles, respectively. Moreover, obtained silver nano-composites show different catalytic activity for the catalytic reduction of p-nitrophenol depending on the carrier system used for preparation.     

Microwave Preparation of Ag Nanoparticles for Chemiluminescence Enhancement

Chemiluminescence applications frequently require signal enhancement. We report a major improvement of the chemiluminescence of luminol in alkaline peroxide solutions by silver nanoparticles prepared by chemical reduction of AgNO₃ by NaH₂PO₂ in ethylene glycol solution, with polyvinylpirrolidone as capping agent and using a simple microwave approach and set up. The luminescence emission is also shown to be much faster. The nanoparticles were characterized spectroscopically and by dynamic light scattering showing an average particle size of 36 nm.     

Enhanced Photocatalytic Efficiency of TiO2 by Combining the Modification of Ag Nanoparticles with the Application of Anodic Bias

Ag-TiO2/TTO film electrode was used as photoanode to investigate the feasibility of a hybrid technology of Ag nanoparticles combined with the application of anodic bias.The results showed that the deposited Ag and applied anodic bias have an apparent additive effect.     

Synthesis of Ultraviolet Absorber Benzotriazole by Nanoparticles Ag/SiO2 Catalytic Hydrogenation

The Ag/SiO2 nanoparticles had been successfully synthesized. The Ag/SiO2 nanoparticles can be an excellent catalyst for the synthesis of ultraviolet absorber benzotriazole by catalytic hydrogenation. The synthesis route is very efficient with less pollution and excellent yields. It is also easy to industrialized production.