Abstract:TiO2 nanotube arrays perpendicular to the substrate were fabricated by anodic oxidation in three different electrolytes: fluoride-free inorganic(HCl H2O2), fluoride-inorganic(HF) and fluoride-organic(EG). The influences of electrolytes on the formation of the tubes were investigated. The morphology of the as-fabricated samples was studied with SEM. The TiO2-NTs were used as photoanodes to photoelectrochemically split artificial seawater into hydrogen. The results show that TiO2-NTs obtained in EG electrolytes have a higher hydrogen evolution activity because of relatively better surface smoothness and tube orderliness, which are benefit for electro-hole pairs transporting and reducing recombination between them.