In this study, porous Bi2O3 catalysts were prepared by the sol gel method, and the effects of polymorphism and pore structure on the photocatalytic activity for hydrogen evolution using Bi2O3 were investigated. The mixtures of beta- and gamma-Bi2O3 prepared using urea showed larger specific surface areas and higher activities for hydrogen evolution than alpha-Bi2O3 prepared without urea. Copyright (C) 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.