BACKGROUND: Water pollution is a serious problem for the entire world. Photocatalysis is an accepted way to decontaminate water. As the key factor influencing photocatalysis, an environmentally friendly photocatalyst should possess good visible-light-response. Additionally, an efficient catalyst should have good separation of e(-)/h(+) pairs. On account of the special f electron orbital structure, the ions of rare earths exhibit the ability to accelerate the abruption of photogenerated e(-)/h(+) pairs. In this work, visible-light-driven alpha-Bi2O3 enhanced using Pr3+ doping was prepared by hydrothermal synthesis. RESULTS: The as-prepared catalysts calcined at 500 degrees C exhibited only the characteristic peaks of Bi2O3 and presented irregular plate-like structures. The separation efficiency for electron-hole was enhanced when alpha-Bi2O3 was doped with Pr. The photocatalytic activities, which were evaluated by degradation of Rhodamine B (RhB) and 2,4-dichlorophenol (2,4-DCP) under visible light irradiation, was enhanced significantly by doping Pr into alpha-Bi2O3. CONCLUSION: Doping alpha-Bi2O3 with Pr significantly enhanced the photocatalytic activity. The optimum percentage of doped pr was 3.0 mol %. center dot OH radicals were the dominant photooxidant. This study demonstrates an efficient pathway to improve the photocatalytic performance of alpha-Bi2O3. (C) 2013 Society of Chemical Industry