Fabrication of ZnWO4 nanofibers by a high direct voltage electrospinning process

Mixtures of zinc acetate dihydrate, ammonium metatungstate hydrate, and 5 wt%, 6 wt%, and 7 wt% of poly (vinyl alcohol) (PVA) were electrospun by a +15 kV direct voltage to produce fibers. In the present research, the electrospun fibers of 6 wt% PVA were further calcined at 400-600 °C for 3 h. The sanmartinite monoclinic structured ZnWO₄ was detected by X-ray diffractometer (XRD) and selected area electron diffraction (SAED), weight loss by thermogravimetric analyser (TGA), morphology and particle size by scanning and transmission electron microscopes (SEM, TEM) and atomic force microscope (AFM), including their vibration modes by Fourier transform infrared spectrometer (FTIR) and Raman spectrometer. The 4.42 eV direct energy gap (E_g) and 460 nm emission wavelength, caused by the electronic transition of (WO₆)²⁻ octahedrons, were determined by UV-visible absorption and photoluminescence (PL) spectrometers. A possible formation mechanism of ZnWO₄ nanofibers was also proposed according to the experimental results.     

Sonochemical synthesis,characterization,and magnetic properties of Mn-doped ZnO nanostructures

Mn-doped ZnO samples,Zn1-xMnxO (x =0,0.01,0.03 and 0.05;mole fraction),were successfully synthesized by sonochemical method.The undoped and Mn-doped ZnO samples...     

Characterization of CoWO4 nano-particles produced using the spray pyrolysis

CoWO₄ nano-particles were produced by spraying the solution containing CoCl₂·6H₂O and Na₂WO₄·2H₂O on glass slides at 250–450 °C. XRD, SAED, TEM, HRTEM and AFM revealed the presence of CoWO₄ nano-particles with their crystallographic planes aligning in systematic array. Raman spectra provide evidence of the wolframite structure, corresponding to the product phase. Their photoluminescence (PL) emissions show the narrow central peaks of the same spectral region at 411–419 nm.