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RESEARCH PRODUCT

Influence of Anodic and Thermal Barrier Layers on Physicochemical Behavior of Anodic TiO2 Nanotubes

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Electrochemical and photo-electrochemical behavior of self-organized TiO2 nanotubes formed in organic solvents have been studied by taking into account the formation of new barrier layers beneath nanotubes either due to the anodic polarization in aqueous solutions or air exposure during high temperature annealing. It has been shown that before annealing, electrochemical and photoelectrochemical answers are dominantly controlled by the physicochemical properties of the anodic barrier layer. Annealing in air at sufficiently high temperatures changes the initial amorphous structure of as-prepared nanotubes and forms a new oxide layer below them due to thermal oxidation of underneath titanium. Affixing tube bottoms to the substrate during annealing, which forms a better electrical contact, can play an important role in collecting a higher photoresponse from annealed nanotubes. In order to improve TiO2 nanotubes performance the role of the new anodic or thermal layers, bridging nanotubes and metal substrate, has to be considered. Anodic Titania NanoTubes (TNTs) have attracted much attention during the last decade due to their particular characteristics such as one-dimensional highly ordered geometry with large surface area and good chemical and optical stability. These properties of TNTs, formed on titanium substrate via anodization, made them a potential candidate to be utilized in several applications such as dye-sensitized solar cells, 1–3 photo-electrochemical splitting of water 4, 5 and hydrogen