TiO2/Bi2O3 photocatalysts for elimination of water contaminants. Part 1: synthesis of α- and β-Bi2O3 nanoparticles

Titanium oxide is a common semiconductor used in heterogeneous photocatalysis. However, TiO2 efficiency is limited because TiO2 absorbs only a small fraction of visible light. An alternative would be to use bismuth oxide (Bi2O(3)) in association with TiO2 because Bi2O(3) has a strong absorption in the visible light region. We have optimized the synthesis of alpha- and beta-Bi2O3, drawing from the two main methods, namely precipitation and hydrothermal synthesis. The structural and light absorption properties of as-prepared composites were determined using different spectroscopic techniques (UV-Vis DRS and XRD). The photocatalytic activity of the beta-Bi2O3 has been compared to commercial and prepared alpha-Bi2O3 for the photodegradation of Orange II under visible and UV light.