Characterization of Bi2S3 nanorods and nano-structured flowers prepared by a hydrothermal method

Bismuth sulfide nanorods and nano-structured flowers were synthesized by hydrothermal reaction of bismuth nitrate pentahydrate and thiourea solutions, containing 1 and 2 ml of 65% HNO₃, respectively. By using X-ray diffraction (XRD), selected area electron diffraction (SAED), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and high resolution TEM (HRTEM), the products were specified as orthorhombic Bi₂S₃ in the shapes of nanorods and flower-like clusters of nanorods, with the growth of nanorods in the [001] direction. A diffraction pattern was also simulated, and was in good accordance with the SAED pattern obtained from the experiment.     

Malic acid complex method for preparation of LiNiVO4 nano-crystallites

LiNiVO₄ nano-crystallites were prepared by the polymerized complex method using Li₂CO₃, Ni(CH₃COO)₂·4H₂O and NH₄VO₃ as starting reagents and malic acid as a complexing agent. With the subsequent calcination at 450 °C, the powder analyzed by XRD, FTIR, Raman, electron diffraction, SEM and TEM techniques was found to be inverse spinel LiNiVO₄ with ∼20 nm in diameter. TGA shows continuous weight loss at 40–450 °C due to the evaporation and decomposition processes. Above 450 °C, weight percent tended to be constant. In addition, formation mechanism of the purified LiNiVO₄ was proposed to relate with the experimental results.     

Solvothermal synthesis of CdS nanowires templated by polyethylene glycol

CdS nanowires were solvothermally synthesized from Cd(NO₃)₂ and S powder using ethylenediamine as a solvent and polyethylene glycol (PEG) as a template. Hexagonal CdS with P6₃mc space group was detected using XRD and SAED, results which are in good accordance with those obtained by the simulation. SEM, TEM and HRTEM revealed the gradual development of nanowires in the [0 0 1] direction with a number of atoms aligning in a crystal lattice. Raman spectra of different products showed the fundamental and overtone modes at the same wavenumbers of 300 and 601 cm⁻¹, respectively. Their relative intensities at different molecular weight PEG were influenced by the anisotropic geometry of the products. Their photoluminescence peaks were detected at the same wavelengths of 518 nm. A formation mechanism for CdS nanowires was also proposed to relate to the experimental results.     

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.     

Silica gel-assisted solvothermal production of CdS,CuxS(x=1,2) and ZnS with different morphologies

CdS, Cu_xS (x=1, 2) and ZnS with different morphologies were produced by the solvothermal reactions of M(CH₃COO)₂·2H₂O (M=Cd, Cu and Zn) and NH₂CSNH₂ in hexane with and without silica gel as a hard template at 200 °C for 24 h. The product phases were detected using X-ray diffraction (XRD). Different morphologies were characterized using a scanning electron microscope (SEM). The existence of silica gel in modeling morphologies of the sulfides was characterized using Fourier transform infrared (FTIR) spectrometer. Raman spectra of different products show the vibrations at the same wavenumbers, although they are composed of different morphologies. Photoluminescence (PL) emissions of the corresponding phases with different morphologies are at the same values, but their intensities are increased by template adding.     

Characterization of SrWO4-PVA and SrWO4 spiders’ webs synthesized by electrospinning

Mixtures of strontium acetate, ammonium metatungstate hydrate, and different contents of poly (vinyl alcohol) (PVA, 125,000 MW) were electrospun by a +15 kV direct voltage to synthesize SrWO₄-PVA spiders’ webs. The spider's web, synthesized from the solution containing 1.3 g PVA, was further calcined in air at 300-600 °C for 3 h. The SrWO₄-PVA spider's web was analyzed by thermogravimetric analyzer (TGA) to specify the evaporation and decomposition of PVA and volatile components. In addition, the SrWO₄-PVA and SrWO₄ spiders’ webs were characterized by X-ray diffractometer (XRD), selected area electron diffraction (SAED), scanning and transmission electron microscopes (SEM, TEM), and ultraviolet (UV)-visible and photoluminescence (PL) spectrometers, including the vibration modes by Fourier transform infrared (FTIR) and Raman spectrometers. A possible formation mechanism of SrWO₄-PVA and SrWO₄ spiders’ webs was also proposed according to the experimental results.     

Hydrothermal synthesis and characterization of Dy-doped CeVO_4 nanorods used for photodegradation of methylene blue and rhodamine B

Pure CeVO_4 and Dy-doped CeVO_4 nanorods containing different weight contents of Dy dopant were synthesized by hydrothermal method.Effect of Dy dopant on photodegradation of methylene blue(MB)and rhodamine B(RhB) was evaluated under UV light irradiation within 80 min.Pure CeVO_4 and Dydoped CeVO_4 nanorods were characterized by X-ray diffraction(XRD),Raman spectroscopy,transmission electron microscopy(TEM) and UV-visible spectroscopy.In this research,CeVO_4 nanorods are tetragonal phase with the detection of main peak shift after being doped with Dy.The length of nanorods is deceased from 50 to 200 nm for pure CeVO_4 to 50-100 nm for 3% Dy-doped CeVO_4.Photodegradation of MB and RhB by CeVO_4 nanorods under UV light irradiation is improved by Dy-dopant that plays the role in accepting electrons and reducing electron-hole recombination.MB and RhB solutions degraded by 3% Dy-doped CeVO_4 nanorods was 94% and 93% within 80 min,respectively.     

Characterization of Li1−x Ni1+x O2 prepared using succinic acid as a complexing agent

Li_1−x Ni_1+x O₂ was prepared by a polymerized complex method using succinic acid as a complexing agent. Ethanolic solutions of lithium acetate dihydrate, nickel acetate tetrahydrate, and succinic acid were mixed to form carboxylate precursors, which were subsequently calcined at 650–800°C for 14–48 h. TGA curves of metal acetates, succinic acid, and the precursors were characterized to determine weight loss and formation temperature of the oxide. By using XRD, SEM, and EDX, pure crystals of Li_1−x Ni_1+x O₂ were detected at 750 and 800°C. The maximum and minimum intensity ratios of XRD spectra show that the optimum calcination condition is 750°C for 40 h. At 650–800°C, the particle size distribution is in the range of 0.35–39 μm. The text was submitted by the authors in English.     

Photocatalytic activity of La-doped ZnO nanostructure materials synthesized by sonochemical method

ZnO nanostructure materials doped with different La contents were synthesized by sonochemical method. The products were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM),transmission electron microscopy(TEM), Raman spectroscopy, and Fourier transform infrared spectroscopy(FTIR). In this research, XRD patterns of pure ZnO and La-doped ZnO are specified as hexagonal wurtzite ZnO structure with no detection of La2O3 phase. SEM and TEM characterization revealed the flower shape of pure ZnO built-up from petals of hexagonal prisms with hexagonal pyramid tips. Upon doping with La, the flower-shaped ZnO is broken into individual 1D prism-like nanorods. Photocatalytic activities of the as-synthesized products were determined by measuring the degradation of methylene blue(MB) under ultraviolet–visible(UV) light irradiation.Among them, the 2.0 mol% La-doped ZnO shows better photocatalytic properties than any other products.     

Facile sonochemical synthesis and photocatalysis of Ag nanoparticle/ZnWO_4-nanorod nanocomposites

A facile sonochemical method was developed to synthesize metallic Ag spherical nanoparticles on the surface of ZnWO_4 nanorods by forming heterostructure Ag/ZnWO_4 nanocomposites.The Ag/ZnWO_4 nanocomposites were characterized by X-ray powder diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),field emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS).The experimental results showed that fcc metallic Ag nanoparticles were supported on surface of monoclinic sanmartinite ZnWO_4 nanorods.The Ag3d_(3/2) and Ag 3 d_(5/2) peaks have well-separated binding energies of 6.00 eV,certifying the existence of metallic Ag.The Ag/ZnWO_4 nanocomposites were evaluated for photodegradation of methylene blue(MB)induced by ultraviolet-visible(UV-Vis)radiation.In this research,heterostructure 10 wt% Ag nanoparticle/ZnWO_4-nanorod composites have the highest photocatalytic activity of 99%degradation of MB within 60 min.The increase in photocatalytic activity was the result of photoinduced electrons in conduction band of ZnWO_4 that effectively diffused to metallic Ag spherical nanoparticles and the inhibition of electron-hole recombination process.