The mesoporous Nb2O5 photocatalysts were synthesized via an evaporation-induced self-assembly (EISA) method. The mesoporous structure of the as-made samples was studied by small-angle X-ray diffraction, N-2 adsorption-desorption isothermal and transmission electron microscopy. The increase of the calcination temperature during the synthesis resulted in enhanced crystallization, but decreased mesoporosity of the samples. The later was found to have a crucial influence on the photocatalytic activity by bringing on decreased BET surface area and especially increscent pore wall thickness. The advantage of the mesoporous Nb2O5 was also proved by performing 20 times higher photocatalytic activity than a bulk Nb2O5 without any porosity. A model was given to describe the effect of mesoporosity on the transportation and recombination of carriers. (c) 2007 Elsevier B.V. All rights reserved.