Enhancing photoelectrochemical properties of titania nanotubes via rapid thermal annealing in hydrogen atmosphere

Abstract

To meet rising worldwide demands for clean electricity, the technologies for affordable, yet efficient photoactive semiconductors are constantly being developed. The high-surface titania nanotubes are typically obtained through the anodization of a titanium foil, but the created structures are amorphous and require crystallization to improve their electric properties. The heat treatment is usually done via time- and energy-consuming furnace annealing, before any modification of the material can be done. In our work, an alternative, one-step calcination method combined with modification through hydrogenation is investigated. The evaluation of the crystallinity of the electrode is presented based on the Raman and X-ray diffraction, followed by the optical and electrochemical investigation providing quantifiable information regarding the performance of the modified material. Overall, the presented one-step calcination and hydrogenation via rapid thermal annealing allows for a much quicker crystallization and simultaneous modification, resulting in over 2.6-fold higher photocurrent densities and improved visible light absorption.