No abstract

Nanocrystalline NiO has been prepared successfully by chemical precipitation route using nickel nitrate hexahydrate (Ni (NO3)2·6H2O) and sodium hydroxide (NaOH) aqueous solution at a temperature of 60 ̊C. Their compositional, structural, morphological, thermal and optical properties were studied using energy dispersive analysis of X-rays (EDAX), X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), ultraviolet-visible (UV-Vis) spectroscopy, photoluminescence (PL) spectroscopy and Raman spectroscopy. From XRD pattern we confirmed the face centered cubic (fcc) structure of the synthesized NiO nanoparticles. The selected area electron diffraction (SAED) pattern indicated the same crystalline planes as seen in XRD pattern. TGA indicates good thermal stability of synthesized NiO nanoparticles and the optical absorption spectrum of NiO nanoparticles shows the strong absorption edge at 235nm (4.10eV). PL spectra of NiO nanoparticles shows two wide emission peaks at 420nm (2.95eV) and 440nm (2.82eV) and a strong–broad peak at 460nm (2.70eV) in violet emission band whereas the Raman peak observed at 518cm-1 shows the Ni-O stretching mode of vibration.

Size-controlled silver nanoparticles are prepared at two different heating time duration (30 and 60min) under conventional heating at 80 ̊C in an aqueous solution of silver nitrate (AgNO3) as a precursor and trisodium citrate (C6H5O7Na3.2H2O) as a reducing agent under continuous stirring. The size and size distribution of the resulting silver nanoparticles prepared under conventional heating are strongly dependent on the duration of heating. As the heating duration is increased, aggregation and grain growth is observed. When duration of heating was 60min a distinct increase in the particles size was observed that lead to shift in the plasmon band as confirmed by UV-Vis absorption spectroscopy. TEM images shows that silver nanoparticles are nearly spherical in shape and their sizes are ranging between 2-42 nm and their cubic structure was confirmed by X-ray diffractogram. From X-ray diffractogram we calculated crystallite size using Scherrer’s equation which comes out to about 36nm and that determined from Hall-Williamson plot turns out to be 19nm.

No abstract

No abstract