Monodisperse porous ZnO nanospheres were successfully fabricated through a facile and cost-effective polyol-mediated preparation approach, followed by annealing at 400 degrees C for 2 h. The photocatalytic activity of the ZnO products was evaluated by the decolorization of rhodamine B (RhB) solution under simulated sunlight irradiation. The effects of operational parameters on the photo-degradation reaction progress, including catalyst dosage, initial dye concentration, reaction temperature, initial pH value, and the addition of inorganic oxidants, transition-metal ions and inorganic anions were investigated in detail. In addition, reactive species in the oxidation of RhB solution were pinpointed by adding a series of scavengers into the photocatalytic reaction system and O-2(center dot)- were determined to be the main reactive species. A potential mechanism of photocatalysis of RhB under simulated sunlight irradiation is proposed. The catalyst is found to be reusable. (C) 2016 Elsevier Ltd. All rights reserved.