Authors
1 Materials and Energy Research Center, Karaj, Iran
2 Materials and Energy Research Center Karaj, Iran
Abstract
NiWO4 nano crystallite was synthesized in low-temperature in polymer media for the first time. The formation reaction between nickel chloride and sodium tungstate occurred at 180 °C for 10 hours in ethylene glycol. Crystallized NiWO4 particles were successfully obtained after calcination at 500 °C for 4 hours. Thermal analysis (TG/DTA) was used to understand the behavior of nickel tungstate under Heat treatment. X-ray powder diffraction (XRD) results showed that the best calcinating temperature was 500°C, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were carried out to show nano sized nickel tungstate crystallites. The crystallite size of this metal tungstate was 17 nm by rietveld calculation with particle size of less than 50 nm according to the TEM images. The study of optical absorption spectrum in the wavelength range 350–500 nm showed the presence of direct band gaps to be 3.41 eV and 3.25 eV before and after calcination, respectively. The largest surface area obtained from the powders heat treated at 100°C was to be 105 m2/gr. Photocatytic test was carried out using methylene blue and by exposing the solution to UV radiation (12 watt) for 1,2 and 3 hours. The obtained results showed satisfying photocatalytic and decolorization properties of NiWO4.
Keywords
)