Using a facile hydrothermal method, pure alpha-Bi2O3 samples with rod-like structure were synthesized. Amorphous Cu(II) clusters were loaded on the as-obtained alpha-Bi2O3 samples by an impregnation method. The prepared samples were characterized by X-ray diffraction, scanning electron and transmission microscopy, X-ray photoelectron spectroscopy, and UV-visible diffuse reflectance spectroscopy. The photocatalytic activities were evaluated from gaseous 2-propanol decomposition under visible light irradiation. It is found that crystal structure and the morphologies were not changed by the Cu(II) clusters modification. Pure Bi2O3 sample showed a limited photocatalytic activity due to its low conduction band edge. After Cu(II) clusters modification, the photocatalytic activity was significantly improved. The Cu(II) clusters play a critical role in the charge separation and efficient oxygen reduction, which explains the enhanced photocatalytic activity. (c) 2013 Elsevier B.V. All rights reserved.