Solid state studies on cobalt and copper tungstates nano materials

The cobalt and copper tungstates of the composition Co 1− x Cu x WO 4 (where x = 0.0, 0.3, 0.5, 0.7 and 1.0) were synthesized by co-precipitation method. The compounds were characterized by Thermogravimetric Differential Scanning Calorimeter, X-ray powder diffraction, Infrared spectroscopy, Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. The Rietveld refinements of X-ray powder diffraction data for the composition Cu 0.5Co 0.5WO 4 reveal the triclinic structure with Pī symmetry. The SEM and TEM studies of the compounds show average particle size in the range of 30–50 nm. The XPS studies confirmed the 2+ oxidation state of the Co and Cu, whereas W exists in 6+ state. The Diffuse reflectance Ultraviolet–visible spectroscopy illustrates band gaps of the compounds ranging from 2.95 to 2.79 eV. The CoWO 4 shows promising photoluminescence result exhibiting strong emission intensity at 468 nm. Mixed metal oxides of cobalt–copper tungstates were derived from solution based co-precipitation method. TEM images indicate that the particle size is in the range 30–50 nm. [Display omitted]