Study of the Photocatalytic Properties of Ni-Doped Nanotubular Titanium Oxide

Nanotubular titanium oxide is widely known as a prospective semiconductor photocatalyst for the process of water splitting. Its photoelectrochemical (PEC) efficiency can be improved by doping with 3d metal. In this work, the synthesis of nanotubular titanium oxide (NTO) was carried out by anodizing titanium substrates using two doping techniques. First, Ni-doped TiO₂ was obtained by immersion in Ni salt solution; second, an ethylene glycol-based fluoride electrolyte containing Ni²⁺ ions solution was used. The obtained samples were analyzed using SEM, XRD, and photoelectrochemical methods. The produced Ni-doped NTO exhibited photocatalytic activity twice as high as that of nondoped NTO. Additionally, it was found that the immersion technique initiated a shift of the incident photon to converted electron (IPCE) spectra to the visible part of the spectrum.