Surface characterisation of spinels with Ti(IV) distributed in tetrahedral

The differences of the binding energy of the Ti 2p electron obtained by X-ray photoelectron spectroscopy (XPS) in ternary spinels 3/2 such as LiFeTiO , LiMnTiO and LiCrTiO have been studied. X-ray diffraction patterns for these spinels and neutron powder diffraction 44 4 data for LiFeTiO , LiMnTiO and LiCrTiO reveal that Fe(III) is in octahedral and tetrahedral sites, and Cr(III) and Mn(III) are 44 4 exclusively in octahedral sites. However, Ti(IV) cations are distributed 100% in octahedral sites for LiFeTiO , 66% in octahedral sites 4 and 34% in tetrahedral sites for LiMnTiO , and 88% in octahedral sites and 12% in tetrahedral sites for LiCrTiO . XPS studies confirm 4 4 the oxidation state of the cations Fe(III), Cr(III), Mn(III) and Ti(IV); and using high resolution XPS (5.85 eV pass energy) it is possible to decompose the Ti 2p signal in two peaks at 458.0 eV (68%) and at 458.7 eV (32%) assigned to octahedral and tetrahedral Ti(IV), 3/2 respectively for LiMnTiO . In the case of LiCrTiO , the Ti 2p signal could be decomposed in two peaks at 458.4 eV (87%) and 459.3 44 3 / 2 eV (13%) with a similar assignation than that observed for LiMnTiO . A single Ti 2p peak at 458.1 eV and corresponding to octahedral 43 / 2 Ti(IV) was observed for LiFeTiO . © 2001 Elsevier Science B.V. All rights reserved. 4