Antimony-doped rutile titanium(IV) oxide

Abstract

Titanium–antimony oxides formed by calcination of precipitates at elevated temperatures have been shown by powder X-ray diffraction, 121Sb Mossbauer spectroscopy, energy-dispersive X-ray analysis, thermal analysis, and temperature-programmed reduction techniques to be materials in which small concentrations of antimony(V) are accommodated within the rutile titanium(IV) oxide lattice. The solids can be envisaged as being derived from the thermally induced dehydration and crystallisation of an initially amorphous titanium–antimony hydroxide precipitate such that the antimony which cannot be accommodated within the rutile lattice migrates to the surface to form a volatile antimony oxide phase. However, an examination of the monophasic antimony-doped titanium(IV) oxide by X-ray photoelectron spectroscopy showed no enrichment of the surfaces by antimony. An investigation of the titanium–antimony oxides by transmission electron microscopy identified planar defects which were shown by electron diffraction to be twin boundaries. The twin boundaries were found to be free of quinquevalent dopant. No evidence has been found for the occurrence of crystallographic shear planes.