, is an object of a very large number of publications and review papers [ 22 – 29 ]. Amadelli et al. [ 30 ] synthesized cobalt-modified TiO 2 by the incipient impregnation method. They found that the modified oxide presents higher photoactivity both under illumination with UV-Vis (λ > 360 nm) and visible light (λ > 420 nm; λ > 450 nm), and that this enhancement depends on the amount of added species and on the final thermal treatment in the preparation step.
Doping of semiconductors changes the probability for charge carriers to participate in conduction. In order