Bi2O3 catalysts have been prepared via precipitation method by using Bi(NO3)(3)(.)5H(2)O as a starting material and NaOH as the precipitating agent. The influence of bismuth concentration on the formation of Bi2O3 nanocrystals was investigated by using XRD, BET, FTIR, SEM and H-2-TPR. Low bismuth concentration, resulted in high surface area material with small size crystallite (similar to36 nm). It also enhanced the oxide reducibility with high reduction activity. XRD patterns of all the samples display pure alpha-Bi2O3 phase. The SEM images showed the nanostructure of Bi2O3 were non-agglomerated needles. (C) 2004 Elsevier B.V. All rights reserved.