Synthesis of TiO2 Nanotube Arrays in NaOH Added Ethylene Glycol Electrolyte and the Effect of Annealing Temperature on the Nanotube Arrays to their Photocurrent Performance

Abstract

The present study employs NaOH as an oxygen source in fluorinated ethylene glycol (EG) electrolyte for the formation of titanium dioxide nanotube arrays (TiO2 NTs) by anodic process. The nanotube formed were 125 nm in diameter with length of ~ 7 µm after 30 min of anodization. They were then annealed to study the effect of annealing temperature on the photocurrent generated by the TiO2 NTs. It is found that TiO2 NTs annealed at 400 °C has the highest photocurrent (0.716 mA cm-2 at 0.5 V vs Ag/AgCl). This is attributed to the crystallinity (mostly anatase) of the TiO2 NTs as well as the nanotubular structure which retains at this temperature but not at higher temperature.