Dc. Sayle et al., COMPUTER-SIMULATION STUDY OF THE DEFECT CHEMISTRY OF RUTILE TIO2, Journal of physics and chemistry of solids, 56(6), 1995, pp. 799-805
We examine the defect chemistry of rutile TiO2 using computer simulati
on techniques. The stable valencies of dopant transition metal ions in
TiO2 are calculated to be Nb(V), V(III), Fe(III) and Cr(III). We find
that Cr3+, Al3+, Ga3+, V3+ and Fe3+ dissolve preferentially at substi
tutional sites in TiO2 with charge compensation by oxygen vacancies ra
ther than Ti4+ interstitials, although experimentally both are observe
d. Nb5+ is calculated to dissolve preferentially at substitutional sit
es with charge compensation being facilitated via Ti(III) ions or tita
nium vacancies. The solution enthalpy of Nb5+ is reduced by the introd
uction of Al3+ into the lattice. The solution enthalpy is further redu
ced when we consider bound Al3+/Nb5+ clusters.