Photoelectrochemical Behavior of 3d Transition Metal Nanostructured film Electrode Doped with TiO₂

The 3d transition metal ions [Cr( III ), Fe( III ), Mn( II ), Co( II ), Ni( II ), Cu( II ), Zn( II )] nanocrystalline doped with TiO₂ (abbr. M^3d-TiO₂) were characterized by AFM and XRD. The M^3d-TiO₂ nanostructured film electroede was prepared and investigated with photoelectrochemical techniques. The results show that the size of M^3d-TiO₂ nanocrystalline particles was quite uniform and the radii were about 15 nm. The M^3d-TiO₂ nanocrystalline particles were a mixture of brookite and anatase crystal forms. Of all the M^3d-TiO₂ investigated in this paper, however, the photocurrent intensity of Zn²⁺-TiO₂ nanostructured film electode was higher than that of the electrode undoped with TiO₂. The phenomenon of p-n type inversion was observed in certain wavelength range, which was caused by 3d transition ions doping.