Anatase TiO2 hierarchical nanospheres were synthesized through a simple way combining dealloying and hydrothermal methods. The photocatalytic activity of the obtained products and Degussa P25 were evaluated by the degradation of methyl orange (MO) aqueous solution at different initial pH values and concentrations. The anatase TiO2 hierarchical nanospheres exhibited excellent photocatalytic activity for the degradation of methyl orange under ultraviolet-visible light irradiation. The photocatalytic efficiency of the anatase TiO2 increased with the decrease of pH at first then decreased and it also decreased with the increase of MO concentration. The superior photocatalytic performance of anatase TiO2 hierarchical nanospheres is attributed to its crystal phase, microstructure, and particularly surface acidity. The enhancement of surface acidity reduces the electron-hole pair recombination, and further increases the photocatalytic efficiency. (C) 2015 Elsevier B.V. All rights reserved.