Incorporation of Ti4+ into layered double hydroxide sheets? The response by X-ray diffraction and absorption study Original Research Article

The incorporation of tetravalent cations Ti4+ into Layered Double Hydroxide (LDH) type materials of cation composition (Co, Al) seems, at a first glance, effective based on the informations obtained by X-ray diffraction. This hypothesis is, however, dismissed by X-ray absorption spectroscopy, since the moduli of the Fourier transform at Ti and Co K-edge do not exhibit simultaneously the features characteristic of the local order for LDHs. The Ti atoms are found to present an environment close to the one observed in TiO2 anatase, with Ti–Ti contact, whereas the Co atoms are located in the LDH sheets, the presence of the focusing effect testifying of the good planarity of the layers. The variation of the cell parameters has then to be considered taking into account a substitution between divalent and trivalent cations.