The traditional hydrothermal method for synthesis of H2Ti3O7 nanotubes was modified, and the total hydrothermal reaction time of forming a matured network of H2Ti3O7 nanotubes was successfully decreased by 50%. The effect of hydrothermal reaction time on morphology and photocatalytic activity of H2Ti3O7 nanotubes was investigated and discussed. Various morphologies can be observed in the as-prepared samples with different hydrothermal reaction times. The photocatalytic activity of the as-prepared samples was evaluated for degradation of methyl orange (MO) under simulated solar irradiation. It was found that the sample treated in the hydrothermal condition for 36 h with a matured network of H2Ti3O7 nanotubes showed excellent photocatalytic activity. The photocatalytic activity results were discussed in detail. The stronger absorption in the ultraviolet (UV) range, the increasing crystallization of H2Ti3O7 phase, and larger surface area and pore volume contributed to the enhancement of photocatalytic activity of the as-prepared samples. (C) 2012 Elsevier B. V. All rights reserved.