Journal of Ultrafine Grained and Nanostructured Materials

Journal of Ultrafine Grained and Nanostructured Materials

Electrochemical Synthesis of Metal- and Nonmetal-Doped TiO₂ Nanotubes for Enhanced Photoelectrochemical Charge Transfer

Document Type : Research Paper

Authors
Mohammed Ahmed Hussein Awad 1
Yasmin M.S Jamil 2
Hussein M.A. Al-Maydama 2
1 Chemistry Department, Faculty of Applied Sciences, Thamar University, Thamar, Yemen.
2 Department of Chemistry, Faculty of Science, Sana'a University, Yemen.
10.22059/jufgnsm.2026.01.10
Abstract
In this work, self-ordered titanium dioxide (TiO₂) nanotubes (NTs) doped with various metal and nonmetal species were synthesized by in-situ electro-anodization to improve the photoelectrochemical (PEC) performance of TiO₂ nanotube arrays. The formation mechanism of the nanotubes was investigated through current density–time (J–t) behavior, which confirmed the successful development of nanotubular structures under all doping conditions. X-ray diffraction (XRD) analysis showed that the as-anodized TiO₂ NTs were amorphous, whereas annealing at 450 °C induced crystallization into the anatase phase. Doped samples, including 0.05 M V-doped TiO₂ NTs–N₂, 0.01 M W-doped TiO₂ NTs–N₂, and 0.05 M Fe-doped TiO₂ NTs–N₂, retained the anatase structure after doping and annealing, and no secondary dopant-related oxide phases were detected by XRD, although the presence of phases below the detection limit or in an amorphous state cannot be excluded. Minor peak broadening was attributed to lattice distortion and defect generation associated with dopant incorporation, which may contribute to improved charge separation and electronic conductivity in TiO₂-based photoelectrodes. Scanning electron microscopy (SEM) further confirmed the formation of vertically aligned and highly ordered nanotube arrays with uniform diameters ranging from 12 to 78 nm. The photoelectrochemical performance of the doped TiO₂ NTs was evaluated under ultraviolet (UV) illumination using linear sweep voltammetry (LSV) and chronoamperometry in three different electrolytes, namely 1 M KOH, 0.5 M H₂SO₄, and 0.5 M Na₂SO₄. Most doped samples exhibited higher photocurrent densities than the undoped TiO₂ NTs, particularly in alkaline media, and KOH produced the highest and most stable photocurrent response among the investigated electrolytes. These findings indicate that both the dopant type and electrolyte environment significantly influence the photoelectrochemical behavior of TiO₂ nanotubes. The improved performance is reflected by enhanced photocurrent generation and operational stability, suggesting more favorable interfacial charge-transfer processes and charge transport at the TiO₂/electrolyte interface under UV illumination.
Keywords
Electrochemical anodization
TiO2 nanotubes
In-situ metal and nonmetal doping
Photoelectrochemical performance
photocatalysts
Electrolyte effects
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Journal of Ultrafine Grained and Nanostructured Materials
Volume 59, Issue 1
June 2026
Pages 126-149

  • Receive Date 10 May 2026
  • Revise Date 20 June 2026
  • Accept Date 21 June 2026