Preparation and photocatalytic properties of Bi-doped TiO2/montmorillonite composite

Abstract To overcome the limitations of narrow light-response range and rapid electron–hole recombination in the TiO2 photocatalytic treatment of dye wastewater, we prepared and systematically studied the Bi-doped TiO2/montmorillonite composite using the sol–gel method. Results showed that Bi enters the crystal lattice of anatase TiO2 in the +3 valence state. The highest photocatalytic activity was achieved when the molar ratio of Bi:Ti was 7%. During the photocatalytic treatment, the degradation extent of rhodamine B reached 90.60% under visible-light irradiation. This high photocatalytic activity results from the doping with Bi3+ ions, which makes the band gap lie between the Ti4+ 3d and Bi3+ 6s bands and inhibits the recombination of electrons and holes.