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

Abstract

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.

Effect of nickel doping concentration on the morphological and structural properties of titanium dioxide nanoparticles

“…Transition metals have various oxidation states which can be incorporated into TiO 2 matrix and act as potential traps for photogenerated e-h pairs, and thus increasing their lifespan by preventing their recombination. Furthermore, transition metal ions such as Fe, Cr, Ni doping promotes the formation of Ti +3 ions, resulting in oxygen defects which facilitates the adsorption of oxygen to titania surface to attain high photocatalytic activity [2], [4][5][6][7]. It was reported that Ni 2+ acts as shallow trapping sites, significantly decreasing surface recombination of e-h pairs.…”

Component Engineering of Multiphase Nickel Sulfide-Based Bifunctional Electrocatalysts for Efficient Overall Water Splitting

“…Although nickel sulfide-based electrocatalysts with different crystal structures have all been separately studied as HER/OER catalysts, the further enhancement of the electrocatalytic activity of these materials is still greatly limited due to their low surface active exposure and poor long-term stability. Doping foreign high-active transition metal into nickel sulfide-based catalysts is regarded as an efficient route to optimize their electrochemical performance by overcoming the intrinsic activation barriers [39][40][41]; however, the doping strategy usually shows a tendency to include the various metal-active sites, leading to a significant impact on the study of intrinsic catalytic activity [42,43]. In principle, the catalytic property of a material is determined using its electronic structure and can be regulated by engineering its composition and morphology [44][45][46].…”