Self-Standing TiO₂ Nanotubular Membranes for Sustainable Production of Energy

Abstract

In this contribution, we present a simple electrochemical approach to obtain large-area free-standing TiO2 nanotube membranes, via a three-step anodic oxidation of pure Ti sheets in fluoride-containing ethylene glycol. The highly ordered vertically oriented TiO2 nanotubes were characterized by Field Emission Scanning Electron Microscopy (FE-SEM) and Glancing Angle X-Ray Diffraction (GA-XRD) analysis. In particular, we report some details related to the synthetic procedure by SEM images of the fundamental steps, evidencing the development of the morphology of the catalytic surface. The study was focused on the ability to control the nanotube morphology, length, pore size, wall thickness and packing degree, by varying some parameters during the synthesis (such as voltage, electrolyte, pH, time of anodization, water concentration, etc.). The 1D nanostructured films (well-ordered vertically aligned TiO2 nanotubes) can be used as electrodic materials for solar devices (dye-sensitized or photo-electrochemical solar cells). Results showed that smooth surface and high aspect ratio TiO2 nanotube arrays were fabricated, which may have wide applications in the development of micro-confined reactors for a sustainable production of energy.