Nanowires of α- and β-Bi₂O₃: phase-selective synthesis and application in photocatalysis

Abstract

This paper is focused on the first selective synthesis of α-and β-Bi2O3 nanowires by an oxidative metal vapour transport deposition technique. The nanowires growth conditions have been systematically investigated, providing insights into the mechanism of nanowires formation. We make a critical comparison of photocatalytic properties of the α- and β-Bi2O3 nanowires by the photo-degradation of Orange G under visible light. The β-Bi2O3 nanowires have shown the highest photo-catalytic activity under visible light of all the tested samples of Degussa TiO2 P25 and α-/β-Bi2O3 nanowires, which can be interpreted by the narrowest band gap of the β-Bi2O3 nanowires for the most effective harvest of the visible light as well as their smallest size for the most facile transfer of photo-excited electrons and the consequent most effective electron-hole separation.