CuInSe2 nanocrystals (NCs) were prepared by colloidal synthesis and immobilized onto TiO2 nanotube arrays (NTs). Photoelectrical properties of the co-sensitized photoelectrode were investigated. The photocatalytic activities were investigated through the photocatalytic degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) and anthracene-9-carboxylic acid (9-AnCOOH). The high photo-electrical efficiency is mainly due to the high absorption toward visible light and the decrease in electron-hole pairs recombination. A well maintained opened TiO2 tube-mouth configuration favors the high photoelectrical efficiency and stability of the CuInSe2/TiO2 NT photoelectrode. The co-sensitized CuInSe2/TiO2 NT photoelectrode displays excellent water splitting ability, 229.35 mu M/cm(2) hydrogen gas was achieved in 210 min. The formation of hydroxyl radicals (center dot OH) on the surface of the CuInSe2/TiO2 NT photoelectrode under visible-light illumination was detected. (C) 2015 Elsevier B.V. All rights reserved.