Enhanced solar water-splitting performance of TiO2 nanotube arrays by annealing and quenching

Abstract

TiO2 nanotube arrays were prepared by a modified two-step anodization, and the effects of annealing temperature and cooling manners on the photoelectrochemical water-splitting performance of TiO2 nanotube arrays were investigated. The results showed that higher annealing temperature and faster cooling rate resulted in higher solar conversion efficiency. TiO 2 nanotube arrays annealed at 650 °C with oil quenching showed maximum solar conversion efficiency of 1.75% under simulated solar illumination. This superior photoelectrochemical water-splitting performance was attributed to high crystallinity by elevated annealing temperature, pure anatase phase and thin barrier layer due to oil quenching, as well as the carbon doping during anodization in organic electrolyte. © 2014 Elsevier B.V. All rights reserved.