Synthesis and characterization of silver nanoparticles by sonoelectrodeposition

Shaped silver nanoparticles with sphere, wire and dendrite were prepared by sonoelectrochemical deposition from an aqueous solution of AgNO3 in the presence of ethylenediaminetetraacetic acid disodium salt （EDTA） and polyvinylpyrrolidone （PVP）. The diameter of spherical silver particles was about 30 nm. The diameter of the silver nanowires was also about 30 nm and the length was 200-900 nm. The dendrites were synthesized with the concentration of silver solution increasing. Silver nanoparticles were characterized by transmission electron microscope （TEM）, X-ray powder diffraction （XRD）, scanning probe microscope （SPM） and UV-vis absorption spectrum. XRD patterns revealed that silver particles were of face-centered cubic structure. UV-vis absorption spectra indicated that different morphology and size of silver particles could influence the optical properties.     

Synthesis and characterization of metallic Pd embedded TiO2 nanoparticles by reverse micelle and sol-gel processing

This research was financially supported by the Ministry of Education, Science Technology(MEST) and Korea Industrial Technology Foundation(KOTEF) through the Human Resource Training Project for Regional Innovation.     

Preparation and characterization of gelatin mediated silver nanoparticles by laser ablation

We successfully prepared colloidal silver nanoparticles (Ag-NPs) using a nanosecond pulsed Nd:YAG laser, λ = 532 nm, with laser fluence of approximately about 0.6 J/pulse, in an aqueous gelatin solution. The size and optical absorption properties of samples were studied as a function of the laser repetition rates. The results from the UV-vis spectroscopy demonstrated that the mean diameter of Ag-NPs increase with the laser repetition rate increases. The Ag-NPs have mean diameters ranging from approximately 9 nm to 15 nm. Compared with other preparation methods, this work is clean, rapid, and simple to use.     

溶剂热法Fe3O4纳米颗粒的制备及表征

以乙醇及水的混和溶剂、单质Fe为原料在高温高压反应釜中制备了Fe3O4纳米颗粒。XRD及红外分析表明所获得产物为Fe3O4。高分辨透射电镜观察表明,Fe3O4具有长棒状形貌,长度为200～500nm,直径为20～30nm。所获得Fe3O4纳米颗粒具有良好的铁磁性能,其饱和磁化强度达到64.75emu/g。讨论了Fe3O4纳米颗粒的形成机制。     

Sodium alginate mediated route for the synthesis of monodisperse silver nanoparticles using glucose as reducing agents海藻酸钠为保护剂葡萄糖为还原剂合成单分散银纳米粒子

报道了一种在水溶液中的简单绿色法制备纳米银溶胶。硝酸银,海藻酸钠素,葡萄糖分别做为银源,保护剂和还原剂。纳米溶胶的颜色从无色变到黄色,表明生成了纳米银粒子。利用透射型电子显微镜（TEM）,紫外可见光谱（UV-vis）和X-射线衍射（XRD）对样品进行了分析。TEM图像表明,所得到的银纳米颗粒的为粒径较小,分散性较好的球状粒子,分布范围较窄,从3 nm 到12 nm。XRD结果表明所得到的纳米金属粒子为单晶的纳米银颗粒。通过UV光谱对反应时间、反应温度、银离子浓度及还原剂的浓度对粒径的影响进行了研究。由于该方法具有无污染、简单、廉价等优点,因此该方法可以做为一种较好的制备纳米银粒子的方法。该方法可以扩展到其它贵金属的技术应用,例如药用,工业应用等。     

溶液法和反胶束法制备Fe-B颗粒的结构和磁性能

采用溶液法和反胶束法合成Fe-B磁性纳米颗粒.通过XRD、TEM、ICP、VSM等手段,依次对Fe-B纳米颗粒的结构、形貌、成分、磁性能进行表征,并针对两种方法所得结果进行对比分析.采用溶液法制备的Fe-B纳米颗粒为晶体结构,颗粒尺寸在20~70 nm;反胶束法合成的Fe-B磁性纳米颗粒一般为非晶结构,颗粒尺寸细小(约5 nm).ICP颗粒成分分析结果表明,两种方法制备的Fe-B颗粒中B含量不同,溶液法制备的Fe-B颗粒中B含量约为17.8 at%;而反胶束法制备的Fe-B颗粒,其B含量较高,达34.9 at%.上述结构、颗粒尺寸和B含量的差异,导致了两种方法合成的Fe-B颗粒在磁性能方面的差别.     

Synthesis of ZnS nanoparticles via hydrothermal process assisted by microemulsion technique

Uniform and spherical ZnS nanoparticles with a diameter of 5–10 nm were successfully synthesized at 160 °C via a facile hydrothermal process, where ZnS precursors were prepared by a microemulsion technique. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and photoluminescent (PL) spectra techniques, respectively. The results showed that the hydrothermal temperature exerted a more important effect than the holding time on the crystallization of ZnS crystallites. The as-prepared ZnS nanoparticles exhibited higher PL intensity than that of the normal ones of micrometer scale besides an obvious blue shift.     

Control of silver throwing power by pulse reverse electroplating

The influence of electroplating parameters on throwing power (TP) is studied in additive-free silver cyanide solutions under direct current and pulse reverse electroplating conditions. It is found that the best TP is obtained when no agitation of the electrolyte is applied. The most important parameters for controlling the TP are the cathodic current density, the anodic to cathodic charge ratio, and the ratio between the anodic and cathodic current densities. Guidelines for process optimisation are given.     

机械化学法制备氮化硼纳米管及纳米粒子

通过高能球磨及随后的退火过程,在同一实验参数下制备了氮化硼纳米管和纳米粒子.制备的氮化硼纳米管呈竹节状,直径为20～100 nm,长度约为几个微米.制备的氮化硼纳米粒子尺寸均匀,大部分呈圆片状,少数为球状;直径为20～100nm,多数粒子直径为70 nm.同一制备参数下形成不同形态氮化硼纳米材料的原因在于氮化硼米管及纳米粒子的形成机理不同.     

One-step reverse micelle polymerization of organic dispersible polyaniline nanoparticles

Organic solvent dispersible dodecylbenzenesulfonic acid (DBSA)-doped polyaniline (PANI) was prepared from DBSA micelles with ammonium persulfate (APS) as an oxidant in hexane by one-step polymerization. Morphology observation showed PANI–DBSA powder polymerized with 0.0375 mol DBSA consisting of spherical particles having diameters of 40–60 nm that formed irregular aggregates with about 1 μm diameter. Polymerization was carried out in the hydrophilic aqueous microdomains of micelle dissolved reactants. The experimental conditions were optimized for direct synthesis of DBSA-doped PANI with high electrical conductivity by adjusting various reaction conditions. This research showed the importance of adjusting reaction conditions such as DBSA, aniline, ammonium persulfate, and acidity for polymerization. It was also found that a portion of an electrically neutral anilinium–DBSA complex could be assembled into reverse micelles together with DBSA molecules, where DBSA and anilinium–DBSA acted as both surfactants and doping agents to achieve nano-scaled DBSA-doped PANI with high conductivity. The doping level of DBSA in PANI particles was studied by UV–vis spectroscopy and X-ray diffraction (XRD). From TG/DTA/mass spectrometry, it was found that the PANI–DBSA was doped with both free and bound DBSA.     

醇热还原法制备纳米金属钌颗粒

报道了利用溶剂热工艺在乙醇溶液中制备胶态纳米金属钌颗粒的方法. 在120.℃热处理不同时间后, 观测到溶剂热还原反应形成不同颜色的中间体. 通过添加醋酸根稳定剂, 在乙醇溶剂中形成晶粒尺寸为3～6纳米的单分散金属钌颗粒. 通过该方法还合成了溴化十六烷基三甲铵(HTAB)包敷的晶粒尺寸为1～5纳米的金属钌粉体.     

Growth of uniform ZnO nanoparticles by a microwave plasma process

ZnO nanoparticle coatings with a controlled size distribution have been grown on quartz substrates by a novel microwave plasma assisted spray (MPAS) technique. This study presents the analysis of structure, photoluminescence, and magnetic properties of particle coatings with two distinctly different mean particle sizes (400 nm and 200 nm). X-ray diffraction patterns show a typical wurtzite structure without any impurity phases for the nanoparticle coatings. SEM and TEM investigations have shown the grown nanoparticles to be spherical and well separated with a narrow size distribution. Nanoparticles are polycrystalline with smaller grain sizes associated with the smaller particle sizes. Photoluminescence (PL) spectra reveal the presence of oxygen vacancy related defects in the 400 nm nanoparticles, which become less pronounced in the 200 nm nanoparticles. The 400 nm nanoparticles are found to exhibit room-temperature ferromagnetism with a clear hysteretic behavior, while the 200 nm nanoparticles are diamagnetic even down to 10 K. These results suggest the oxygen vacancies were the cause for defect-induced ferromagnetism in the 400 nm nanoparticles.     

Solvent effects in the synthesis of MgFe2O4 nanopowders by reverse micelle processing

Nanopowders of MgFe₂O₄ have been synthesized by the novel and facile reverse microemulsion route. The effects of changing the continuous phase on the particle size and the magnetic property have been studied. The average particle size, morphology and saturation magnetization are shown to be dependent on the continuous phase. The average diameters of the particle prepared with heptane are 20.9 ± 4.3 nm. On the contrary, the product with toluene and cyclohexane is highly aggregated. The values of saturation magnetization for our samples prepared with heptane, toluene and cyclohexane are 14.5, 30 and 37 emu/g.     

Synthesis of high-purity silver colloids using a thermal decomposition method

A thermal decomposition method was employed to produce high purity Ag particles. Silver carbonate was dispersed in an H₂O solvent that was heated above 80°C, followed by rapidly injecting H₂O₂ into the solvent. Then, the silver carbonate was decomposed into nanosized Ag particles using the decomposition heat of hydrogen peroxide as follows: Ag₂CO₃→2Ag+CO₂+1/2O₂. The size of the synthesized Ag particles is approximately 100 nm. This method can be used to produce high-purity Ag colloids withuut impurities, unlike other methods.     

银氧化锡合金废料电解综合回收工艺研究

采用直流电解法和化学法回收银氧化锡(AgSnO2)合金废料中的银和锡。优化得到的电解银工艺参数为:槽电压1.5~3.0 V,电解周期为24 h,电解液中Ag⁺浓度为150~260 g/L,HNO3浓度为15~20 g/L,同极距120~140 mm,极板排布为六阴极五阳极间隔交替排列。一个周期银氧化锡废料电解银直收率接近95%,主体纯银粉在阴极析出。富含氧化锡的阳极泥和残极用硝酸浸出少量残余银,不溶渣还原熔炼回收锡,硝酸浸出的含银溶液中加入氢氧化钠调节pH值到10,沉淀得氧化银,500℃焙烧得到单质银。废料中的银和锡均得到有效回收。全流程银的回收率不低于99%。     

Synthesis of Ag/SiO2 nanosize particles by reverse micelle and sol-gel processing

Ag/SiO₂ composite particles have been synthesized within reverse micelle via metal alkoxide hydrolysis and condensation. The size of the particles and the thickness of the coating can be controlled by manipulating the relative rates of the hydrolysis and condensation reactions of tetraethoxysilane (TEOS) within the microemulsion. The average size of the synthesized particles was in the size range of 20–40 nm. The effects of synthesis parameters, such as the concentration of the Ag solution, the molar ratio of water to TEOS, and the molar ratio of water to surfactant, are discussed.     

AOT reverse micelle, a new organized medium for the electrosynthesis of polyaromatic hydrocarbons; application to the electropolymerization of biphenyl

Electrosynthesis of poly(biphenyl) (PBP) films was performed in an AOT [sodium bis(2-ethylhexyl) sulfosuccinate] reverse micelle by cyclic voltammetry and chronopotentiometry on a platinum electrode. An electroactive PBP film was formed either by cyclic voltammetry between −0.6 and 1.65 V/Ag/AgCl or under current control (j = 0.2 mA/cm²). PBP films were characterized electrochemically and spectroscopically (MALDI-TOF mass spectrometry), NMR, Raman, FT-IR, X-ray photoelectron and UV–vis spectroscopy). The structure of the PBP films involved sequences of ramified trimer possessing quinoid forms. This type of sequences can give strongly condensed oligomers with PBP molar mass up to 2669.6 g/mol according to the electrosynthesis charge.     

非水溶液体系中晶种法制备球形银纳米颗粒

以丙三醇作溶剂,硝酸银为原料,聚乙烯吡咯烷酮(PVP)为分散剂,硼氢化钠为还原剂制备了银纳米晶种;以此银纳米粒子作为初级晶种,以丙三醇作溶剂和还原剂,通过升温提高丙三醇的还原性制备银纳米颗粒。研究分散剂种类、生长液银浓度、晶种加入量对银粉的影响,采用X射线粉末衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)、透射电子显微镜(TEM)对制备产物的结构、物相、形貌进行表征。结果表明,通过改变条件可以制备出分散性良好、粒径均匀的70 nm左右的球形银粉。     

Preparation and formation mechanism of Al2O3 nanoparticles by reverse microemulsion

Al2O3 nanoparticles were prepared by polyethylene glycol octylphenyl ether（Triton X-100）/n-butyl alcohol/cyclohexane/ water W/O reverse microemulsion. The proper calcination temperature was determined at 1 150 ℃ by thermal analysis of the precursor products. The structures and morphologies of Al2O3 nanoparticles were characterized by X-ray diffraction, transmission electron microscopy and UV-Vis spectra. The influences of mole ratio of water to surfactant on the morphologies and the sizes of the Al2O3 nanoparticles were studied. With the increase of surfactant content, the particles size becomes larger. The agglomeration of nanoparticles was solved successfully. And the formation mechanisms of Al2O3 nanoparticles in the reverse microemulsion were also discussed.     

球形纳米银粉体制备及其表征

采用均匀沉淀和高温热分解相结合的方法制备了纳米银粉体,分析了纳米银粉体形成机理,研究了初始浓度、烧结温度和时间对纳米银粉体粒径和形貌的影响;采用X射线衍射仪、扫描电子显微镜表征了纳米银粉体结构、组成、大小和形貌。结果表明,硝酸银初始浓度0.05 mol/L、烧结温度300℃、烧结2 h,以尿素为pH控制剂,不添加任何其他分散剂条件下可得到分散性好、颗粒均匀,粒径50 nm的球形粉体。