Electron paramagnetic resonance (EPR) room-temperature observation of triva
lent titanium in sol-gel titania has been reported, This unprecedented dete
ction of stable paramagnetic signals in this titania, which was treated at
200 degrees -800 degreesC, occurred regardless of whether the atmosphere wa
s reducing, inert, or oxidating, The possibility that the paramagnetic sign
als may originate from an metal impurity other than titanium was completely
excluded by analyzing the samples using three different ion-beam-analysis
techniques: Rutherford backscattering spectroscopy, particle-induced X-ray
emission resonance, and energy-recoil detection analysis. The paramagnetic
signals appeared at precisely the temperature range of the sample dehydroxy
lation, which suggests a mechanism for explaining these Ti3+ EPR spectra.