Effect of Thermal Annealing on the Structural and Optical Properties Nanostructured Cobalt‐Manganese and Cobalt‐Nickel Oxides Prepared by Co‐Precipitation

摘要

Cobalt‐Manganese and Cobalt‐Nickel oxide (CoMnO and CoNiO) nanoparticles were synthesized via chemical co‐precipitation method by decomposition of their respective metal sulfides and sodium carbonate using ethylene diamene tetra acetic acid as the capping agent. The samples were heated at 400, 600 and 800?°C. The average particle sizes were determined from the X‐ray line broadening. The diffractogram were compared with JCPDS data to identify the crystallographic phase and cubic structure of the particles. The samples were characterized by XRD, FTIR and UV analyses. The internal elastic micro strains were calculated and it was seen that as the particle size increases strain decreases. The FTIR studies have been used to confirm the metal oxide formation. The chemical compositions of the samples were verified using EDX spectra. The surface morphologies of the samples were studied from the SEM images. The absorption spectra of the materials in the UV‐Vis‐NIR range were recorded. From the analysis of the absorption spectra, the direct band gaps of the materials were calculated.