Synthesis of hollow CuS nanostructured microspheres with novel surface morphologies

Hollow CuS nanostructured microspheres with novel surface morphologies were synthesized by a facile precipitate-converting reaction. The products were characterized by SEM, XRD, BET measurements and size analysis. The surfaces of the hollow CuS microspheres showed acicular, rod-like, concavo-convex and flat morphologies respectively when using different amounts of thioacetamide as precipitants. The diameters of the hollow CuS microspheres could be tuned to a certain extent by using Cu₂(OH)₂CO₃ microspheres with different sizes as precursors. A solid–solution–solid mechanism for the formation of the hollow CuS nanostructured microspheres was discussed. The method reported here also could be applied for the synthesis of other nanostructured microspheres.     

Synthesis of CdS nanocrystals with different morphologies via an ultraviolet irradiation route

A simple ultraviolet photochemical reduction synthetic approach to preparing CdS nanocrystals with different morphologies is described. Sodium dodecyl sulfate (SDS) was used as soft template for the chemical synthesis of CdS nanocrystals in a mixture solution at room temperature. It was found that the magnetic force stirring and the volume proportions of C₂H₅OH and H₂O had marked influences on the morphology of CdS nanocrystals (such as spherical, acicular-like, rod-like and worm-like shapes). The formation of CdS is via precipitation of Cd²⁺ ions with the homogeneously released S²⁻ ions from decomposition of thioacetamide under ultraviolet irradiation source. X-ray diffraction (XRD), scanning electron microscopy (SEM) and the ultraviolet–visible (UV–vis) absorption spectra were employed to characterize the products. This novel method is expected to produce various semiconductor nanocrystals with potential applications in the fields of materials science and photovoltaic cells, etc.     

Synthesis of silver particles with different sizes and morphologies

In this work, using a simple templateless, surfactantless, chemical reduction method, we synthesized micron-sized silver particles with different sizes and morphologies by simply changing the reaction conditions, specifically, the amount of ascorbic acid added to a silver nitrate aqueous solution, the Ag⁺:Ascorbic Acid molar ratios used were 1:1, 1:2, 1:3 and 1:4. The morphologies obtained were polyhedrons and dendrites. The sizes of the particles ranged from 1.5 μm to 15 μm. The principal driven force which produces the changes in the morphology of the Ag particles could be the variations in the electrochemical potential aroused from the changes in the amount of ascorbic acid used in the reaction.     

Synthesis and characterization of different morphologies CuGaS<Subscript>2</Subscript>/CuS nanostructures with a simple sonochemical method

In this experimental work, different morphologies of CuGaS₂/CuS nanostructures were synthesized via a simple ultrasonic method. The effect of different parameters was investigated on the product size and morphology, such as copper source, sulfur source, ultrasonic power and time, solvent and the reaction vessel. It was found the mentioned parameters have significant effects on the product size and morphology. The obtained products were characterized by X-ray diffraction pattern to study the product structure and scanning electron microscopy was used to study the products morphologies.     

Synthesis of hollow structural hydroxyapatite with different morphologies using calcium carbonate as hard template

Hydroxyapatite (HAp) with hollow structure was successfully synthesized by hydrothermal process of as-prepared calcium carbonate used as a hard template and calcium sources in a diammonium phosphate solution. Calcium carbonate was fabricated by precipitation, which possessed different morphologies such as balls, rods and blocks through regulating the amount of citric acid. The synthesized powders were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrograph (FT-IR), field-emission scanning electron microscope (FESEM) and high-resolution transmission electron microscopy (HRTEM) and nitrogen adsorption–desorption. Results indicated that different morphologies calcium carbonate could convert to hollow structural HAp with the higher BET surface area and the mesopores. Hydrothermal temperature and hydrothermal time play a slight role on transition percentage. As hydrothermal temperature and hydrothermal time increased, the conversion rate of calcium carbonate to hydroxyapatite increased. The possible formation mechanism of hydroxyapatite was preliminarily investigated. The resultants of HAp are interesting materials for drug delivery and sustained-release.     

Characterization of Bi2S3 with different morphologies synthesized using microwave radiation

Bi₂S₃ with different morphologies (nanoparticles, nanorods and nanotubes) was synthesized using bismuth nitrate pentahydrate (Bi(NO₃)₃·5H₂O) and two kinds of sulfur sources (CH₃CSNH₂ and NH₂CSNH₂) in different solvents (water, ethylene glycol and propylene glycol) via a microwave radiation method at 180 W for 20 min. X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicated that all of the products are orthorhombic Bi₂S₃ phase of nanoparticles, nanorods and nanotubes, influenced by the sulfur sources and solvents. Formation mechanisms of the products with different morphologies are also proposed.     

Synthesis and characterisation of CuS nanomaterials using hydrothermal route

Copper sulphide (CuS) nanomaterials with interesting morphology were synthesised using copper nitrate trihydrate, thiourea and water as a solvent by a simple hydrothermal route. A systematic investigation was carried out to investigate the effect of reaction time (5, 16 and 24?h) at 150°C on the morphology of the materials. Without the use of any template or additives, shape controlled synthesis of CuS nanocrystallites were achieved. The possible mechanism for the formation of the various nanostructures of CuS in this system is discussed. The prepared materials were characterised by X-ray diffraction, field emission scanning electron microscopy (FE-SEM) and DRS-UV–Vis absorption analysis. The UV–Vis spectrum shows that it is the promising material which can absorb in the visible region and hence could be used for photocatalytic applications. In addition, the electrochemical characteristic of the synthesised material was investigated by cyclic voltammetric analysis, which shows that CuS could be used for electrocatalytic applications.     

Synthesis of amorphous Si nanowires from solid Si sources using microwave irradiation

Si nanowires were synthesized from Si wafers and from thin Si films deposited on various substrates by microwave irradiation. The power and time were key determinants of the diameter and morphology of the synthesized Si nanowires. The nanowires had an amorphous structure due to the extremely high heating rate. Carbon coating of the Si nanowires was easily achieved by introducing acetylene after synthesizing the nanowires. Carbon-coated Si nanowires are potential candidates for use as the anode material in next generation Li-ion batteries.     

Characterization of MMoO4 (M = Ba, Sr and Ca) with different morphologies prepared using a cyclic microwave radiation

Scheelite molybdates (MMoO₄, M = Ba, Sr and Ca) were successfully prepared by the reactions of M(NO₃)₂·2H₂O and Na₂MoO₄·2H₂O in propylene glycol and NaOH using a microwave radiation. The phases were detected using XRD and SAED. TEM analysis revealed the presence of micro-sized bi-pyramids with a square base, nano-sized particles in clusters, and dispersed nano-sized particles for BaMoO₄, SrMoO₄ and CaMoO₄, respectively. Diffraction patterns of the bi-pyramids were simulated, and are in accord with the experimental results. Raman and FTIR spectra provide the evidence of scheelite structure with Mo-O stretching vibration in MoO₄²⁻ tetrahedrons at 742-901 cm^− 1.     

微波强化制备银基蒙脱土研究

在微波强化条件下通过离子交换法制备了银基蒙脱土(Ag-MMT),与传统溶液离子交换法相比具有反应时间短、工艺简单、能耗少和阳离子交换容量高的优点。系统的研究了微波强化时间、硝酸银溶液浓度和微波功率等对Ag-MMT的银离子负载量的影响,并在模拟体液环境中测定了Ag-MMT中Ag+缓释性能,用傅里叶转换红外光谱(FT-IR)对材料进行了分析和表征。     

Rapid synthesis of Bi2S3 nanocrystals with different morphologies by microwave heating

Single-crystalline Bi₂S₃ nanocrystals with urchinlike and rod-like morphologies have been successfully synthesized using Bi₂O₃, HCl, Na₂S₂O₃ and ethylene glycol (EG) by a simple and fast microwave heating method. Both urchinlike and rod-like Bi₂S₃ nanostructures could be formed under microwave heating at 190 °C for 30 s. Urchin-like Bi₂S₃ nanostructures were prepared using sodium dodecyl sulfate (SDS) or in the absence of any surfactant. However, Bi₂S₃ nanorods were obtained in the presence of cetyltrimethylammonium bromide (CTAB). The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), electron diffraction (ED) and ultraviolet-visible (UV-Vis) absorption spectra.     

Fabrication of CuS nanocrystals with various morphologies in the presence of a nonionic surfactant

Shape-controlled synthesis of CuS nanorods, nanoflakes, and flowerlike structures has been achieved simply in the presence of a nonionic surfactant polyethylene glycol (PEG20000) by adjusting hydrothermal temperature. The as-synthesized CuS nanocrystals were investigated by various techniques of XRD, TEM, SEM, and UV–vis spectra. The electron diffraction pattern indicated that the CuS nanoflakes were single crystals. In the process, the temperature and the surfactant PEG20000 were found to play important roles in determining the morphology of CuS nanocrystals.     

水热法制备不同形貌的氧化锌纳米结构

采用水热法,用甲酰胺水溶液和锌片建立反应体系,在不同种晶层上制备出不同形貌的ZnO纳米结构,所用基底有Si片、镀有ZnO薄膜的Si片、镀有ITO薄膜的Si片、涂有ZnO粉末的Si片等,研究了不同的种晶层对ZnO纳米结构的形貌的影响。在不同温度下,分别在镀有ZnO薄膜和ITO薄膜的医用载玻片衬底上生长ZnO纳米结构,研究了温度在水热法中的作用及种晶层对纳米杆长度的影响。实验中用扫描电子显微镜（SEM）和X射线衍射仪（XRD）对纳米聚集体进行了表征。SEM表征结果表明不同种晶层上获得的ZnO纳米结构形貌差异很大;反应时间、甲酰胺水溶液浓度以及反应温度对ZnO纳米阵列形貌都有着一定的影响;在ZnO薄膜上生长的纳米杆较在ITO薄膜上生长的纳米杆长。SEM图像同时表明氧化锌纳米杆随着温度的增大,纳米杆的长度和杆径增大。X射线衍射峰在34.6℃有很强的（002）纤锌矿衍射峰,该峰表明衬底上有高度c轴取向的大面积纳米杆阵列和较好的结晶质量。     

Synthesis of nanosize BPO4 under microwave irradiation

Nanosize BPO₄ was synthesized using H₃BO₃ and H₃PO₄ (85%) as raw materials under microwave irradiation. This reaction was performed at powers lower than 640 W and irradiation time ranging from 2.5 min to 5 min, which were only a fraction of the time required for conventional synthetic procedures. The structure of the as-prepared BPO₄ is analogous to that of a high cristobalite. The particle sizes of the samples irradiated at 640 and 400 W range from 40 nm to 90 nm and 30 nm to 60 nm, respectively. The effects of different conditions on the experimental outcome are also discussed.     

Synthesis and characterization of pyrite (FeS2) using microwave irradiation

A procedure using microwave irradiation was studied to develop a fast and reliable method for synthesizing pyrite. Pyrite was successfully synthesized within a few minutes via reaction of ferric iron and hydrogen sulfide under the influence of irradiation by a conventional microwave oven. The SEM-EDX study revealed that the nucleation and growth of pyrite occurred on the surface of elemental sulfur, where polysulfides are available. Compared to conventional heating, using microwave energy results in rapid (<1 min) formation of smaller particulates of pyrite. Higher levels of microwave power can form pyrite even faster, but faster reaction can lead to the formation of pyrite with defects.     

Synthesis of gold nanoparticles using pluronic F127NF under microwave irradiation and catalytic effects

This study examined the synthesis of gold nanoparticles with pluronic F127NF and KAuCl4 in water under non-classical conditions. The gold nanoparticle products were well dispersed in water and characterized by ultraviolet-visible spectroscopy and transmission electron microscopy. The reaction time for the synthesis was investigated by monitoring the change in color and the peak of the UV-vis spectra under microwave conditions. The gold nanoparticles were used as a catalyst for the reduction of 4-nitrophenol to 4-aminophenol with NaBH4. The resulting product was confirmed by UV-vis spectroscopy and liquid chromatography-mass spectroscopy.     

Preparation of CdS and ZnS nanoparticles using microwave irradiation

Nanoparticles of CdS, ZnS have been prepared by a very simple fast reaction between CdCl₂ or Zn(Ac)₂ and thioacetamide in aqueous solution using microwave irradiation. The nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), reflectance and photoluminescence spectra. The sizes of the sample as prepared were calculated by Debye–Scherrer formula according to XRD spectra to be about 9 and 3 nm for CdS and ZnS, respectively. Similar results can also been obtained in the TEM images.     

Synthesis and luminescence of Bi0.95Eu0.05PO4 nanocrystals with different morphologies

Bi_0.95Eu_0.05PO₄ nanocrystals with different morphologies were synthesized by precipitation in different solvents. The Bi_0.95Eu_0.05PO₄ samples were characterized by X-ray powder diffraction, scanning electron microscopy (SEM), and luminescence spectroscopy. The X-ray diffraction results reveal that the Bi_0.95Eu_0.05PO₄ samples present a hexagonal phase. The SEM observations demonstrate that the Bi_0.95Eu_0.05PO₄ samples with different morphologies could be obtained in different solvents. The room temperature luminescent properties of Bi_0.95Eu_0.05PO₄ samples were studied using an excitation wavelength of 290 nm. The emission spectra display the bands associated to the ⁵D₀ → ⁷F_J electronic transitions characteristics of the Eu³⁺ cations at different positions.     

Synthesis of silver nanoparticles using N 1, N 2-diphenylbenzamidine by microwave irradiation method

Silver nanoparticles have been prepared under microwave irradiation from a solution of silver nitrate in the presence of N ¹,N ²-diphenylbenzamidine (DPBA) or simply amidine without any stabilizing agent. Different morphologies of silver colloids with charming colors could be obtained using N ¹,N ²-diphenylbenzamidine (DPBA). The structures of silver colloids were determined by TEM. UV-Vis spectroscopy was used to follow the reaction process and to characterize the optical properties of the resultant silver colloids. The influence of unconventional reducing agent on the morphology of silver was investigated.     

Doughnut-shaped hierarchical Cu2ZnSnS4 microparticles synthesized by cyclic microwave irradiation

For the first time, hierarchical doughnut-shaped Cu₂ZnSnS₄ (CZTS) microparticles were synthesized by microwave-assisted solution method. N,N-dimethylformamide and polyvinylpyrrolidone (PVP) were used as solvent and stabilizing agent respectively, and the results showed that PVP played an important role in the formation of hierarchical nanostructures. Structural analysis by X-ray diffraction and Raman studies confirmed the formation of single phase kesterite CZTS. Morphological analysis by scanning electron microscope showed doughnut-shaped CZTS microparticles composed of large number of interpenetrating nanoplates. Optical analysis by UV–Vis diffused reflectance spectra showed strong absorption in the visible region with an optical band gap of 1.54 eV. Asymmetric broad emission bands around 1.55 eV and 1.30 eV were observed in the photoluminescence spectrum. A possible formation mechanism for doughnut-shaped CZTS microparticles was put forward and discussed briefly.