BiOBr photocatalysts with various morphologies have been synthesized via a solvothermal method in ethanol-, ethylene glycol (EG)- and glycerol (GR)-mediated conditions, respectively. The effects of different solvents on the size and morphology of BiOBr crystal are investigated in detail. Viscosity of the solvents is believed to be a key factor in determining morphology of BiOBr crystal, which leads to the different formation mechanisms. In addition, it is found that the photocatalytic activities of BiOBr samples for the degradation of methyl orange (MO) under visible light irradiation are dependent on the solvent used in the synthesis. The differences in the photocatalytic activities are mainly attributed to the different morphologies, which further results in the difference in Brunauer-Emmett-Teller (BET) surface areas, bandgaps, the exposed crystal facets and porous structures. (c) 2012 Elsevier Ltd. All rights reserved.