Bismuth oxide (Bi2O3) is a well-studied photocatalyst for degradation of various environmental con-Taminants. In this research Bi2O3 has been synthesized by precipitation method using two different bases (NH4OH and NaOH). The samples thus obtained were then analyzed using FTIR, XRD, and SEM for surface functionalization, crystal structures and morphological differences, respectively. The Bi2O3 precipitated using NH4OH showed a flower like structure made up of individual plates having α-Bi2O3 crystal structure. The precipitate obtained using NaOH showed a honeycomb like flower struc-Ture with a mixture of both α-Bi2O3 and γ-Bi2O3 crystal structure. Degradation of methyl orange (MO) was used as a model system to test the photocatalytic activity of the bismuth oxide. The Bi2O3 synthe-sized using NH4OH showed superior photocatalytic degradation of methyl orange than the one synthe-sized using NaOH. © 2017 BCREC Group. All rights reserved.