Energy Storage of NiO/TiO<sub>2</sub> Bilayer Films and its Effectiveness in the Degradation of Acid Orange 7

Abstract

The concept of storing energy in TiO2when it was illuminated with light and using the catalyst when there was no light was tested for the first time. Ni(OH)2was incorporated into TiO2for the energy storage purpose. Ni(OH)2was subjected to three different temperatures (300 – 500°C) before the incorporation. NiO/TiO2bilayer films were prepared with spin-coating method. The films were tested for its electrochemical and photoelectrochemical properties in 1 M NaOH. The NiO/TiO2 film prepared with Ni(OH)2calcined at 300°C showed energy storage potential. The catalysts were then investigated for their catalytic activity in the photocatalytic degradation of acid orange 7 (AO7). The experiments were carried out in a batch reactor containing 500 ml of 20 ppm AO7 and 0.2 g NiO/TiO2bilayer film. The reaction were carried out under UV illumination for 2 h before continuing without the illumination (dark condition) for another 2 h. NiO/TiO2showed photcatalytic properties even without illumination implying that the energy stored during the illumination drove the photocatalytic reaction.