The present work reports the preparation of porous delta-Bi2O3 nanospheres via a solvothermal treatment of Bi(NO3)(3)center dot 5H(2)O in the mixed solvent of ethanol and glycerol. The glycerol is found to play a vital role in the formation of delta-Bi2O3 nanospheres not only the particle shapes and sizes, but also the porous structures. The delta-Bi2O3 nanospheres are converted into semi-metallic rhombohedral bismuth inheriting the morphological properties in the presence of NaBH4. Furthermore, the reduction reaction of nitrobenzenes into anilines can be highly achieved over the in-situ formed bismuth porous nanospheres. This work may provide a new method for the preparation of porous bismuth and bismuth oxides, and open the way to a range of important application of bismuth compounds. (C) 2015 Elsevier Ltd. All rights reserved.