Advances in Titania Nanotubes Development by Anodization and Their Role in Solar-Driven Water Splitting

Abstract

The study investigates the fabrication and characterization of titanium dioxide (TiO₂) nanotubes synthesized via a two-electrode anodization process, with a focus on their application in solar-driven water splitting for sustainable hydrogen production. TiO₂ nanotubes were fabricated on titanium foils by anodizing in a 0.5% M ammonium fluoride (NH₄F) solution in ethylene glycol, using a range of applied voltages (12, 20, and 30 V) for a duration of 2 h. The resultant TiO₂ nanotubes exhibited an average diameter of 85 nm and an average length of 1.4 μm, demonstrating a highly ordered and uniform structure, as observed via field emission scanning electron microscopy (FESEM). The crystallinity and phase composition of the TiO₂ nanotubes were investigated through X-ray diffraction (XRD), which revealed that the nanotubes predominantly retained the anatase phase, known for its high photocatalytic efficiency. Optical properties were further examined using UV–Vis absorption spectroscopy, which indicated a characteristic absorption edge around 380 nm, corresponding to a bandgap of 3.2 eV. This suggests that the material predominantly absorbs ultraviolet (UV) light, limiting its use under natural sunlight. However, these properties indicate the potential for further enhancement through techniques such as doping or cocatalyst integration to improve visible light absorption and overall photocatalytic efficiency. The findings demonstrate that TiO₂ nanotubes, with their high surface area and well-defined structure, exhibit favorable characteristics for photocatalytic water splitting. This work highlights the efficiency of the anodization technique in fabricating TiO₂ nanotubes with desirable properties for solar hydrogen production. The results suggest that future work aimed at optimizing the material through doping or the integration of cocatalysts could further enhance its performance in solar-driven water splitting, contributing to the development of sustainable energy solutions.