Synthesis, Modification and Optical Characterization of Co-Cr Layered Double Hydroxide

Abstract

 Cobalt and chromium based layered double hydroxides (LDHs) have been successfully synthesized by the co-precipitation method at a constant pH of 10. The intercalation of stearic acid (C₁₈H₃₆O₂₎ into CoCr-LDH and preparation of their polymer nanocomposites using two different methods were studied in the paper. The obtained samples were characterized before and after modification by X-ray diffractometry (XRD) and Ultraviolet visible (UV-Vis) spectroscopy. It has been shown that different reaction temperature profoundly affects the band-gaps of inorganic and composite structures.Three optical band gap values (E_g1, E_g2 and E_g3) for the samples obtained before and after modification. Two optical band gap values were estimated in polymer/LDH nanocomposites. The high-value band gaps for CoCr-LDH_(100°C)- NBR and CoCr-LDH_(100°C)-SA- NBR were determined to be 5.9 eV and 5.7 eV, respectively. The low-value band gaps for CoCr-LDH_(100°C)-NBR and CoCr-LDH_(100°C)-SA- NBR were determined to be 4.1 eV and 3.25 eV, respectively.