“ACS Reagent Chemicals” expands

Abstract

The photocatalytic splitting of water into hydrogen and oxygen using solar light is a potentially clean and renewable source for hydrogen fuel. 1,2 There has been extensive investigation into metal-oxide semiconductors such as TiO 2 ,WO 3 , and Fe 2 O 3 , which can be used as photoanodes in thin-film form. 3 - 5 Of the materials being developed for photoanodes, TiO 2 remains one of the most promising because of its low cost, chemical inertness, and photostability. 6 However, the widespread technological use of TiO 2 is hindered by its low utilization of solar energy in the visible region. In this study, we report the preparation of vertically grown carbon-doped TiO 2 (TiO 2 - x C x ) nanotube arrays with high aspect ratios for maximizing the photocleavage of water under white-light irradiation. The synthesized TiO 2 - x C x nanotube arrays showed much higher photocurrent densities and more efficient water splitting under visible-light illumination (> 420 nm) than pure TiO 2 nanotube arrays. The total photocurrent was more than 20 times higher than that with a P-25 nanoparticulate film under white-light illumination.