TiO₂ thin films are known to promote photodegradation of dyes and pollutants in water solution via heterogeneous photocatalysis. This ability is guided by the photoexcitation through photons having energies above the band gap. To improve photocatalytic activity, nanostructures with high surface area can be applied, which can ease molecular adsorption/desorption mechanisms, enhance electronic transfer properties and lower excitation energy. For this purpose, square cross-section TiO₂ vertically aligned nanorod (TNR) array configuration has been chosen as a semiconductor substrate. On top of it, a thin layer of sub-stoichiometric TiO_2−x has been deposited, aiming at inducing a vacancy doped homojunction between two different oxygen rich/deficient TiO₂ layers, possibly leading to lower band gap and enhanced photochemical activity. In principle, promotion of electron and holes separation and suppression of charge recombination could occur. Vertically aligned TNRs have been deposited through a hydrothermal growth in acidic conditions on a pre-seeded glass conducting substrate, optimizing the seeding process through spin coating. Sub-stoichiometric TiO_2−x layer (50 nm nominal thickness) has been deposited on top of TNRs via radiofrequency magnetron sputtering at three different stoichiometries, tuning the oxygen partial pressure in sputtering argon atmosphere at 10 %, 15 % and 20 %, respectively. Photocatalytic activity has been investigated in the photodegradation of an aqueous solution of methylene blue, both under UV and simulated solar light irradiation at room temperature and atmospheric pressure, resulting in the degradation of methylene blue target molecule up to 99 % under UV and 85 % under simulated solar irradiation after 6 h. These promising achievements unlock new environmental applications for enhanced dye degradation industrial processes.

已知TiO ₂薄膜通过多相光催化促进水溶液中染料和污染物的光降解。这种能力是由光激发通过能量高于带隙的光子来引导的。为了提高光催化活性，可以应用具有高表面积的纳米结构，这可以简化分子吸附/解吸机制，增强电子转移性能并降低激发能。为此，已选择方形横截面 TiO _{2垂直排列的纳米棒 (TNR) 阵列配置作为半导体基板。}在其顶部，沉积了一层亚化学计量的 TiO _2−x薄层，旨在在两种不同的富氧/缺氧 TiO 之间诱导空位掺杂同质结₂层，可能导致较低的带隙和增强的光化学活性。原则上，可以促进电子和空穴分离并抑制电荷复合。垂直排列的 TNR 已通过在酸性条件下的水热生长沉积在预先接种的玻璃导电基板上，通过旋涂优化接种过程。亚化学计量的 TiO _2−x层（50 nm 标称厚度）已通过射频磁控溅射以三种不同的化学计量沉积在 TNR 顶部，将溅射氩气氛中的氧分压分别调整为 10%、15% 和 20%。在室温和大气压力下，在紫外线和模拟太阳光照射下，研究了亚甲蓝水溶液光降解的光催化活性，导致亚甲蓝目标分子在紫外线下降解高达 99%，在紫外线下降解高达 85% 6 小时后模拟太阳辐射。这些有前途的成就为增强染料降解工业过程开启了新的环境应用。