Stability of TiO 2 nanotube arrays in photoelectrochemical studies

Abstract

Photoelectrochemical (PEC) hydrogen generation gives an opportunity to acquire energy by means of clean and renewable resources such as water and solar light. A major problem in the PEC system is the stability of the photoanode material for long-term applications. Recently, self-assembled titanium dioxide (TiO 2) semiconductors (and their hybrids) have shown potential to generate hydrogen in the PEC system. In the present investigation, stability of the nanotubular TiO 2 in 1 M KOH solution under illumination conditions is investigated. The photoanode is found to be stable (in terms of activity and morphologically) for one month (8 h/day) without much change in the hydrogen generation rate. Possible photoelectrochemical reactions that can be responsible for degradation of performance of nanotubular TiO 2 material are identified. Various spectroscopic and electrochemical measurements, viz., SEM, XRD, DRUV-Vis and Mott–Schottky are employed to confirm that the nanotubular TiO 2 photoanode can be used for long-term applications.