| Description: |
The exhaustion of non-renewable resources emphasises the urgent need for a shift to renewable energy, with green hydrogen production standing out as a key alternative. This research explores the synthesis of TiO 2 nanotubes (TiO 2 -NTs) via anodization. This study demonstrates the successful synthesis of tailored titania (TiO₂) nanotube arrays through electrochemical anodization at controlled voltages (12V, 20V, and 30V) for enhanced photoelectrochemical hydrogen generation. The anodization voltage emerged as a critical parameter governing nanotube morphology, with 12V producing only surface cracks, while higher voltages yielded well-defined tubular structures. At 20V, nanotubes exhibited an average diameter of 42.2 nm and wall thickness of 13.5 nm, while 30V conditions produced larger structures with 66.7 nm diameter, 15.8 nm wall thickness, and increased porosity (60%). X-ray diffraction analysis confirmed the formation of anatase crystalline phase across all voltage conditions, with crystalline sizes ranging from 33.9-45.4 nm. The photoluminescence intensity demonstrated an inverse correlation with applied voltage, indicating enhanced charge separation efficiency at higher voltages. Photoelectrochemical water splitting performance showed progressive improvement with increasing anodization voltage, achieving hydrogen evolution rates of 0.08, 0.12, and 0.20 mL h⁻¹ for 12V, 20V, and 30V respectively, with corresponding PEC efficiencies of 3.20%, 4.63%, and 7.18%. The enhanced performance at 30V is attributed to the synergistic effects of increased surface area, higher porosity, optimal anatase crystallinity, and improved charge carrier separation. These findings establish anodic voltage tuning as an effective strategy for engineering high-performance TiO₂ photoanodes, with the 30V-synthesized nanotubes demonstrating superior morphological characteristics and photoelectrochemical efficiency for sustainable solar hydrogen production applications. |