Ionization of ionic defects leads to the formation of electronic
defects (electrons and electron holes), which are responsible for
the charge transport. It was shown that defect disorder is closely
related to reactivity, photoreactivity, and the related charge
transfer. Therefore, knowledge of defect disorder is essential
to assess the reactivity and photoreactivity. TiO2 is not an
exception. Accordingly, defect chemistry may be used as a
framework for the processing of TiO2 with enhanced photoreactivity
with water and its solutes.