Comparative Optic Studies of Cobalt-Based Layered Double Hydroxides with Nitrate and Carbonate Anions and Co II /A1 III ratio n = 2, 3, 4

The variations of Raman and optic absorption spectra of Co-Al layered double hydroxides (LDH) intercalated with nitrate and carbonate anions have been studied as a function of the $Co^{2+}/A1^{3+}$ ratio. It was revealed from the comparative analysis of the hydrogen bond frequencies in Raman spectra and the phonon repetition lines in optic absorption spectra that the increasing $Co^{2+}/A1^{3+}$ ratio results in an enhancement of the anion exchange ability in nitrate LDH and in a suppression of the ability in carbonate LDH.