Studies of neat kaolin and cobalt (III) oxide dopped kaolin for heterogeneous catalysts development using Fourier transform infrared spectroscopy

Abstract

Mesoporous Co3O4/kaolin as a potential heterogeneous catalyst was prepared by the method of impregnation and its infrared spectroscopic absorption was recorded from 4000 – 650 cm^-1 and the resultant peaks obtained were compared with the infrared absorption peaks of the neat kaolin that was used to prepare the former and also the infrared spectra of Co₃O₄ on various clay minerals found on the related literatures. The result of the analyses indicated two sharp absorption bands at 3688 cm^-1 and 3623 cm^-1 on both the spectra of the neat kaolin and that of the Co₃O₄/kaolin. However, the two sharp peaks were observed to have decreased intensities on the spectrum of the latter, probably due to the effect of doping the kaolin with cobalt nitrate hexahydrate and the subsequent thermal treatment it undergoes. The spectrum of the Co₃O₄/kaolin was observed to have developed a broad absorption band from 3650-3200 cm^-1 associated with the bending and stretching vibrations of the hydroxyl groups of the chemisorbed water molecules attached to the Co₃O₄/kaolin. The peak on the spectrum of Co₃O₄/kaolin at 1334 cm⁻¹ is associated with the stretching vibrations of C–O and also the medium peak at 739 cm^-1 is due to the vibrations of Co(III)-O bonds, and these two peaks confirmed the formation of cobalt oxide kaolinite bond, and this bond between the cobalt oxide and the kaolinite that actually enhances the catalytic ability of the kaolinite and also to have heterogenized the oxides of cobalt that was produced on thermal treatment of the cobalt (ii) nitrate hexahydrate doped kaolin.