X-ray, thermogravimetric and electron spin resonance study of the ReOx–TiO2 system

Abstract

Titanium dioxide containing a few percent of rhenium (up to 6.95% by weight) has been investigated by electron spin resonance at liquid-helium temperatures and by X-ray diffraction and thermogravimetry.

The specimens were treated first in a hydrogen stream at 773 K and then fired at 1273 K in a nitrogen atmosphere. This treatment resulted in rhenium both on the surface and in solid solution in the rutile structure. The rhenium on the surface is found as the metal and as Re^VII bound to titanium dioxide. The rhenium in the solid solution is present as Re^IV.