Large-scale synthesis of WO3 nanoplates by a microwave-hydrothermal method

Tungsten oxide (WO₃) nanoplates were synthesized by a 270 W microwave-hydrothermal reaction of Na₂WO₄·2H₂O and citric acid (C₆H₈O₇·H₂O) in deionized water. X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED) were used to reveal the synthesis of WO₃ complete rectangular nanoplates in the solution of 0.2 g citric acid for 180 min, with O-W-O FTIR stretching modes at 819 and 741 cm⁻¹, and two prominent O-W-O Raman stretching modes at 804 and 713 cm⁻¹. The 2.71 eV indirect energy gap, and 430-460 nm blue emission wavelength range of WO₃ complete rectangular nanoplates were determined using UV-visible and photoluminescence (PL) spectrometers. The formation mechanism was also proposed according to the experimental results.     

Solid-state synthesis of cubic ZnTe nanocrystals using a microwave plasma

Cubic ZnTe nanocrystals were produced from 1:1 and 1.8:1 molar ratios of Zn:Te by a 900 W microwave plasma. The phase was detected using X-ray diffraction (XRD), which are in accordance with those of the simulations, and selected area electron diffraction (SAED). Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that the products were nanocrystals with different orientations, including three longitudinal optical (LO) vibrations at 205, 410 and 620 cm^? 1 and a transverse optical (TO) vibration at 166 cm^? 1. Their green emissions were detected at 562 nm (2.21 eV) using luminescence spectrophotometry.     

Transient solid-state production of nanostructured CuS flowers

CuS (hcp) with different morphologies was produced using a transient solid-state reaction by the direct flow of electricity through solids, containing 1:1 molar ratio of Cu:S powders, in a high vacuum system for different lengths of time. X-ray diffraction (XRD), selected area electron diffraction (SAED), and scanning and transmission electron microscopies (SEM and TEM) specified that the products were nanostructured CuS flowers, and nanostructured CuS composing of nanoparticles with different orientations, controlled by the length of time. Raman vibrations were detected at 474.5 cm^− 1, and photoluminescent (PL) emissions at 347.5 nm. Both the XRD and SAED patterns are in accordance with those obtained by the corresponding simulations.     

Transformation of cubic AgBiS2 from nanoparticles to nanostructured flowers by a microwave-refluxing method

Cubic AgBiS₂ nanoparticles and flower-like clusters were successfully synthesized by microwave refluxing of CH₃COOAg, Bi(NO₃)₃·5H₂O and thiosemicarbazide (NH₂NHCSNH₂) in ethylene glycol. The phase was detected by X-ray diffraction (XRD) and selected area electron diffraction (SAED). The SAED pattern was also in accordance with that of the simulation. Scanning and transmission electron microscopy (SEM and TEM) revealed the gradual transformation of nanoparticles into flower-like clusters by increasing microwave power. Their UV–visible absorption and photoluminescence (PL) emission were detected by spectrometry. Possible formation mechanism of nanoparticles and nanostructured flowers was also proposed according to the experimental results.     

Morphology development of ZnO produced by sonothermal process

Wurtzite ZnO (hcp) was produced by the 80 °C sonothermal reactions of 1:5, 1:10, and 1:20 molar ratios of Zn(NO₃)₂·6H₂O:NaOH in water, containing 2 g, 5 g, 10 g, and 20 g of polyethylene glycol (PEG) with the molecular weights (MWs) of 6000, 10000, and 20000 for 1 h, 3 h, and 5 h. ZnO phase with different morphologies was detected. When the amount of NaOH, both MW and the amount of PEG, and the experimental time were increased, the products still retain their single phase, but their morphologies were changed from nanoplates in clusters to nanospears with sharp tips gathering together in the shape of flowers, and long nanorods with oval tips in clusters. In the present work, formation mechanism of these products was also discussed.     

The effect of solvents on ZnS nanostructures synthesized by biomolecule-assisted solvothermal method

Nanostructured ZnS (hexagonal and cubic) were synthesized by a 200 °C and 24 h solvothermal reaction of Zn(CH₃COO)₂·2H₂O and l-cysteine (C₃H₇NO₂S) in water, propylene glycol (PG) and glycerol (GR) solvents. The products, characterized by XRD, were specified as pure ZnS (hexagonal) in water, and ZnS (cubic) in PG and GR. SEM and TEM analyses showed the particle sizes and agglomerated behaviors, mainly related to the reaction media, which were in accordance with BET adsorption of nitrogen, with blue shift energy gaps relative to the bulk.     

Cyclic microwave-assisted synthesis of Cu3BiS3 dendrites using l-cysteine as a sulfur source and complexing agent

Nanostructured Cu₃BiS₃ dendrites were successfully synthesized from CuCl, BiCl₃ and l-cysteine in ethylene glycol (EG), using cyclic microwave radiation (CMR). The phase was detected by X-ray diffraction (XRD) and selected area electron diffraction (SAED), and was in accordance with that obtained by the simulation. Scanning and transmission electron microscopic (SEM and TEM) techniques revealed the gradual transformation of nanoparticles to nanostructured dendrites, due to the increase of microwave power. Photoluminescence of Cu₃BiS₃ dendrites was a blue emission centered at 367 nm.     

Preparation of LiNiVO4 nano-powder using tartaric acid as a complexing agent

LiNiVO₄ was prepared from Li₂CO₃, Ni(CH₃COO)₂·4H₂O and NH₄VO₃ using tartaric acid as a complexing agent with 1:1–1:4 mole ratios of metals:tartaric acid and subsequent calcination at 350–700 °C for 6–12 h. Inverse spinel LiNiVO₄ was detected using XRD. FTIR and Raman analyses revealed the presence of stretching band of VO₄ tetrahedrons. Only Ni, V and O were detected by EDX. The 1:4 mole ratio for the product with 450 °C calcination for 6 h analyzed by SEM, TEM and electron diffraction (ED) composes of LiNiVO₄ nano-powder with 10–30 nm in diameter.     

Biomolecule and surfactant-assisted hydrothermal synthesis of PbS crystals

PbS crystals were hydrothermally synthesized using Pb(NO₃)₂, l-cysteine, and N-cetyl pyridinium chloride in solutions with different pH values at 140 °C. Flower-like, granular and truncated cubic PbS crystals composing of Pb and S were detected using an X-ray diffractometer (XRD), a scanning electron microscope (SEM), a transmission electron microscope (TEM), a selected area electron diffraction (SAED) technique and an energy dispersive X-ray (EDX) analyzer. In addition, a Raman spectrometer revealed the presence of the first and second overtone modes at 436 and 602 cm⁻¹, respectively. Emission spectra of the products were detected at 412 nm using a photoluminescence (PL) spectrometer.     

Microwave-assisted synthesis of CePO<Subscript>4</Subscript> nanorod phosphor with violet emission

Monoclinic and hexagonal CePO4 nanoparticles and nanorods were successfully synthesized from Ce(NO3) 3·6H2O and Na3PO4·12H2O solu-tions at pH 1-5 by a 180 W microwave radiation for 60 min.The products were characterized by X-ray diffraction(XRD) ,Fourier transform infrared(FTIR) spectroscopy,and scanning electron microscopy(SEM) .XRD patterns revealed that the products are hexagonal CePO4 structures at pH 2-5,and monoclinic CePO4 structures at pH 1.SEM characterization shows that these products were nanoparticles,short nanorods,and long nanorods,controlled by the pH of the precursor solutions.Optical properties of the nanorods were also investigated by ultraviolet-visible(UV-vis) and photoluminescence(PL) spectroscopy.