Preparation of single-crystal copper ferrite nanorods and nanodisks

This article, for the first time, reports the preparation of single-crystal copper ferrite nanorods and nanodisks. Using amorphous copper ferrite nanoparticles synthesized by reverse micelle as reaction precursor, single-crystal copper ferrite nanorods were synthesized via hydrothermal method in the presence of surfactant polyethylene glycol (PEG), however, copper ferrite nanodisks were prepared through the same procedures except the surfactant PEG. The resulting nanomaterials have been characterized by powder X-ray diffraction (XRD), selected electron area diffraction (SEAD), and transmission electron microscopy (TEM). The bulk composition of the samples was determined by means of X-ray photoelectron spectroscopy (XPS).     

Ag_2S纳米粒子的合成与表征

以油酸钠为表面活性剂、硝酸银和硫脲为反应物,在甲苯-水两相界面处合成了Ag_2S纳米粒子。采用紫外-可见吸收光谱(UV-Vis)、透射电子显微镜(TEM)和广角X射线衍射(WAXD)等方法对Ag_2S纳米粒子的光学性质、形貌及晶体结构进行了表征。结果表明,通过改变甲苯-水两相界面反应体系的条件,可以得到粒子尺寸窄分布的Ag_2S纳米粒子;WAXD测定表明所合成的Ag_2S纳米粒子具有单斜结构。     

Synthesis of crystalline MgO nanoparticle with mesoporous-assembled structure via a surfactant-modified sol-gel process

Highly crystalline MgO nanoparticles with the mesoporous-assembled structure were synthesized via a modified sol-gel process with the aid of a structure-directing surfactant under mild conditions. X-ray diffraction (XRD), transmission electron microscopy (TEM), and selected-area electron diffraction (SAED) analyses revealed that the synthesized MgO possessed high crystallinity with the particle size in nanosized range. N₂ adsorption-desorption and pore size distribution analyses indicated that its pore size distribution was in a narrow mesoporous range, which originated from an assembly of the MgO nanoparticles.     

"Green" synthesis of size controllable Prussian blue nanoparticles stabilized by soluble starch

"Green" and size-controlled Prussian blue (PB) nanoparticles have been synthesized using soluble starch as protective agent. The transmission electron images (TEM) showed that the average dimensions of the monodispersed.PB nanoparticles could be tuned from 5 to 20 nm by using different concentration of starch. X-ray diffraction (XRD) analysis further identified a face-centered cubic structure of the nanoparticles. Investigations of optical properties of nanoparticles were also conducted with FT-IR and UV-vis spectroscopy. Moreover, cyclic voltammograms (CV) showed that the starch-PB nanoparticles kept their intrinsic electrochemical properties. The utilization of environmentally benign and renewable starch as the protecting agents offers numerous benefits ranging from environmental safety to integration of these nanomaterials to biologically relevant systems.     

直流电弧放电法合成In2O3纳米粒子

电弧放电法因能在瞬间产生高温使原料气化而成为一种高效的纳米材料制备方法。以金属In为原料,在无催化剂的条件下,采用直流电弧放电法直接合成了In2O3纳米粒子。XRD、SEM和TEM结果表明所制备的In2O3纳米粒子为立方结构,形貌为结晶良好的八面体,平均粒径为60～120nm。纳米粒子之间以点接触和面接触相连。     

Nanomaterials based on CdS nanoparticles in polyethylene matrix

The synthesis of CdS nanoparticles stabilized in the bulk of a polyethylene matrix is described. The size of synthesized nanoparticles is determined by means of transmission electron microscopy. The composition of nanoparticles is defined by X-ray phase analysis. It is shown that the variation of the process-dependent parameters during synthesis of nanoparticles in a polymer + oil solution melt results in the formation of CdS nanoparticles with average sizes of 4.9, 5.4, and 6.2 nm with a reasonably narrow size distribution and well-formed structure. The optical properties of synthesized nanomaterials are investigated. The investigation of Raman scattering reveals softening of the LO-phonon mode with decreasing CdS nanoparticle size. A broad high-energy band of photoluminescence connected with the exciton annihilation in conditions of size quantization is detected.     

Large scale synthesis and characterization of Ni nanoparticles by solution reduction method

Ni nanoparticles were mass synthesized by solution reduction process successfully. The influence of the parameters on the particle size of Ni nanoparticles were studied and the referential process parameters were obtained. The morphology and structure of the synthesized Ni nanoparticles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area analysis and infrared spectroscopy (IR). The results show that Ni nanoparticles are of high purity and are covered by hydroxyethyl carboxymethyl cellulose (HECMC) layer and the mean size being about 31 nm. The magnetic measurement revealed that Ni nanoparticles are ferromagnetic.     

Size-controlled synthesis, microstructure and magnetic properties of Ni nanoparticles

Ni nanoparticles with different mean diameters of 15-83 nm were synthesized by solution reduction process. The size of Ni nanoparticles can be controlled by varying the concentration of NiCl₂·6H₂O and synthesis temperature. The samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), infrared spectroscopy (IR) and X-ray photoelectron spectroscopy (XPS). Results show that the synthesized particles are single-phased Ni with a face-centered cubic crystal structure. Magnetic measurements indicate that Ni nanoparticles are ferromagnetic. The lattice constants and coercivities of the samples are size-dependent.     

Synthesis of Fe3O4@PbS hybrid nanoparticles through the combination of surface-initiated atom transfer radical polymerization and acidolysis by H2S

A versatile approach to fabricate nanoparticles with multiple functionalities through the combined use of both surface-initiated ATRP and acidolysis by H2S techniques was demonstrated. The hybrid nanoparticles exhibited the core-shell structure having the magnetite nanoparticles as the core and the polymethacrylate as the shell with PbS nanoparticles distributing in the shell. The structure and morphology of the synthesized nanoparticles were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The optical and magnetic properties of the nanoparticles were investigated by UV-Vis spectroscopy, photoluminescence spectroscopy and vibrating sample magnetometer (VSM), respectively. It is observed that the absorption and emission behaviors of the Fe3O4@PbS hybrid nanoparticles were seriously influenced by the ATRP time and the reaction time with H2S. The saturated magnetization (Ms) decreased with the increase of ATRP time due to the formation of thicker shells coating on the surfaces of magnetite nanoparticles.     

Synthesis, characterization and photocatalytic evaluation of visible light activated C-doped TiO2 nanoparticles

We have demonstrated heterogeneous photocatalytic degradation of microcystin-LR (MC-LR) by visible light activated carbon doped TiO(2) (C-TiO(2)) nanoparticles, synthesized by a modified sol-gel route based on the self-assembly technique exploiting oleic acid as a pore directing agent and carbon source. The C-TiO(2) nanoparticles crystallize in anatase phase despite the low calcination temperature of 350 °C and exhibit a highly porous structure that can be optimized by tuning the concentration of the oleic acid surfactant. The carbon modified nanomaterials exhibited enhanced absorption in the broad visible light region together with an apparent red shift in the optical absorption edge by 0.5 eV (2.69 eV), compared to the 3.18 eV of reference anatase TiO(2). Carbon species were identified by x-ray photoelectron spectroscopy analysis through the formation of both Ti-C and C-O bonds, indicative of substitution of carbon for oxygen atoms and the formation of carbonates, respectively. Electron paramagnetic resonance spectroscopy revealed the formation of two carbon related paramagnetic centers in C-TiO(2), whose intensity was markedly enhanced under visible light illumination, pointing to the formation of localized states within the anatase band gap, following carbon doping. The photocatalytic activity of C-TiO(2) nanomaterials was evaluated for the degradation of MC-LR at pH 3.0 under visible light (λ > 420 nm) irradiation. The doped materials showed a higher MC-LR degradation rate than reference TiO(2), behavior that is attributed to the incorporation of carbon into the titania lattice.     

Synthesis of Ag modified vanadium oxide nanotubes and their antibacterial properties

Vanadium oxide nanotubes (VO_x-NTs) modified by highly dispersed Ag nanoparticles have been synthesized via a facile silver-mirror reaction. The crucial factors that affected the preparation of the Ag modified vanadium oxide nanotubes (Ag/VO_x-NTs) have been also studied. The dispersion and structure of Ag nanoparticles in the obtained materials were characterized by transmission electron microscopy (TEM), electron diffraction (ED) and X-ray diffraction (XRD). The results showed the distribution and size of the formed Ag particles were greatly influenced by the concentration of AgNO₃ solution. Typically, Ag nanoparticles were well dispersed on the VO_x-NTs with the size range from 3 to 10 nm. The corresponding antibacterial tests demonstrated the as-synthesized Ag/VO_x-NTs exhibited strong antibacterial activity against Escherichia coli (E. coli).     

Synthesis of wurtzite ZnS nanocrystals at low temperature

Nanocrystallites of wurtzite hexagonal ZnS have been successfully synthesized without using any capping agent by simple chemical precipitation method at a low calcination temperature of 150 °C. It has been found that the size of the synthesized ZnS nanocrystallites decreases as Zn²⁺:S^2? ratio is decreased. The synthesized nanoparticles have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis absorption spectroscopy and M–H characteristics. The XRD patterns have confirmed that the prepared ZnS nanoparticles are of wurtzite hexagonal phase. XRD, SEM and TEM studies have shown the decrease in the particle size with the increase in S^2? source. TEM images have clearly shown that size distribution of the particles lie in the range of 5–30 nm. The optical absorption bandgap of the synthesized nanocrystals has been found to be in the range of 3.69–3.74 eV. Magnetization study has shown the ‘diamagnetic’ behavior of synthesized ZnS nanocrystallites with a weak ferromagnetic behavior in the low field regime. The observed weak ferromagnetism has been understood due to the presence of defects in the synthesized ZnS nanoparticles.     

Structural and optical characterization of ZnO doped PC/PS blend nanocomposites

PC50%/PS50% polymer blend nanocomposites, undoped and doped with different concentration of ZnO nanoparticles (1, 2, 3 wt%), have been prepared using solution casting method. Structural and optical studies have been performed using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Ultraviolet–Visible spectroscopy (UV–Vis). ZnO nanoparticles have been synthesized by chemical route method. The nanostructure of the ZnO nanoparticles has been ascertained through X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). Optical Absorption Spectra has been used to study optical constants of prepared blend nanocomposites. Energy band gap of PC/PS – ZnO blend nanocomposites have been calculated by using Tauc relation. The band gap of the nanocomposites decreases as ZnO wt% increases. Extinction coefficient, refractive index and real & imaginary part of dielectric constants increase with increase in ZnO nanoparticles wt%.     

Octahedral cuprous oxide synthesized by hydrothermal method in ethanolamine/distilled water mixed solution

Octahedral cuprous oxide has been synthesized by a simple hydrothermal method using copper sulphate and sodium hydroxide as raw materials in ethanol amine/distilled water mixed solution. The synthesized cuprous oxide powders were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy. XRD pattern exhibited that the nanocrystalline nature with cubic structure for the synthesized nanostructures. Analysis results reveal that pH value of solution plays an important role in the formation of octahedron shape for cuprous oxide. A probable formation mechanism of octahedral cuprous oxide is also proposed.     

Comparative Studies of Microwave and Sol–Gel-Assisted Combustion Methods of NiFe<Subscript>2</Subscript>O<Subscript>4</Subscript> Nanostructures: Synthesis,Structural, Morphological,Opto-magnetic,and Antimicrobial Activity

Nickel ferrite NiFe₂O₄ nanoparticles (NPs) were successfully synthesized by using nickel nitrate, ferric nitrate, citric acid, and ethyl cellulose as a surfactant by a simple sol–gel-assisted combustion method (SACM) and microwave-assisted combustion method (MACM). Structural, morphological, optical, and magnetic properties of the obtained powder were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), photoluminescence (PL) spectroscopy, and vibrating sample magnetometry (VSM). XRD results show that the resultant powder was pure crystalline with cubic structure. The average crystalline size was found to be 18.8 and 10.2 nm synthesized by SACM and MACM, respectively. FT-IR spectra indicate the type of bonds between Ni–O and Fe–O (metal and oxygen). SEM images show that the morphology of the powder consists of well-defined structure. VSM results showed a ferromagnetic behavior of the sample. Antimicrobial activity of NiFe₂O₄ nanoparticles was performed. Both sample 1 (SACM) and sample 2 (MACM) show good inhibition in the zone 100 μg/ml. While comparing, sample 2 shows high inhibition than sample 1.     

壳聚糖/硫化汞纳米复合材料制备与表征

用Hg(NO3)2和TAA为原料,以壳聚糖为模板于室温条件下在水溶液中合成了粒度分布均匀、分散性好的HgS纳米粒子。产物为球形的多晶粒子,平均粒径为20nm,属于立方闪锌矿结构。合成的纳米晶具有良好的光学性能,与体相材料相比表现出明显的量子尺寸效应。用XRD、TEM-SAED、HRTEM、Uv-vis、FT-IR和PL等实验手段对产物进行了分析和表征,并对HgS纳米晶的形成机理进行了初步探讨。     

Preparation and characterization of nanometer-scale powders ceria by electrochemical deposition method

Ceria (CeO₂) nanoparticles of 10-30 nm in average particle size have been synthesized via electrochemical deposition method in cerium(III) chloride solution with an undivided cell as electrochemical cell and ethanol-acetylacetone as additives. X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transformation infrared spectroscopy (FT-IR) and thermal analysis (TG-DTA) are introduced to characterize the samples. The results indicate that the as-prepared powders after being treated at 650 °C are nanocrystalline with the cubic fluorite structure and the sphericity in shape. It is revealed that the size of ceria nanoparticles can be decreased effectively by adding the ethanol-acetylacetone solution. In addition, the possible formed mechanism of CeO₂ nanometer-scale powder. The role of additive is also investigated in this paper.     

Synthesis of vanadium-doped tin oxide nanocrystallites for CO gas sensing

Vanadium-doped tin oxide nanoparticles have been synthesized by a hydrolysis and co-precipitation method from vanadium(III) acetylacetonate and tin tetrachloride. Addition of vanadium species into the tin oxide matrix resulted in a decrease in the grain size, as indicated by X-ray diffraction (XRD) and electron microscopy. X-ray photoelectron spectroscopy (XPS) revealed an interaction between tin and vanadium atoms in the mixed oxide structure and the presence of oxygen vacancies and vanadium cations with multiple oxidation states in the surface region. The binary solid solution exhibited a higher sensitivity to CO gas than pure tin oxide, after both were evaluated in a semiconductor gas sensor. Results demonstrate the feasibility of vanadium dopant for use to enhance sensor response.     

Preparation of Pt-Ru-Ni ternary nanoparticles by microemulsion and electrocatalytic activity for methanol oxidation

Ternary platinum-ruthenium-nickel nanoparticles are prepared by water-in-oil reverse microemulsions of water/Triton X-100/propanol-2/cyclohexane. Nanoparticles formed in the microemulsions are characterized by transmission electron microscopy (TEM), electron diffraction (ED), X-ray diffractometry (XRD), energy dispersive X-ray analysis (EDX). These resulting materials showed a homogenous alloy structure, the mono-dispersion and an average diameter of 2.6 ± 0.3 nm with a narrow particle size distribution. The composition and particle size of ternary Pt-Ru-Ni nanoparticles can be controlled by adjusting the initial metal salt solution and preparation conditions. Pt-Ru-Ni ternary metallic nanoparticles showed an enhanced catalytic activity towards methanol oxidation compared to Pt-Ru bimetallic nanoparticles.     

Small angle neutron scattering and photoluminescence property of wet chemistry process synthesised ZnO nanoparticles

We report the synthesis of zinc oxide (ZnO) nanoparticles from aqueous solution at 25°C and subsequent heating of the solution at 115°C by the suitable selection of the solution chemistry and the control of the alkaline conditions. The structure of the synthesised ZnO particles was studied by X-ray diffraction (XRD), confirming the formation of Wurtzite structure. The optical property of synthesised ZnO nanoparticles is investigated through room temperature photoluminescence (PL) measurement. The PL of ZnO nanoparticles shows a strong UV emission band at approximately 385 nm, a blue–green band at approximately 473 nm and a very weak green band at approximately 554 nm, although polydispersity of the sample shows no presence on the PL spectrum. Small angle neutron scattering is used to determine the size and the size distribution of ZnO nanoparticles. The SANS data analysis and model fitting predict the size as about 18–20 nm, which is closely matched with XRD and transmission electron microscopy results with Gaussian distribution.