Effect of lanthanum and lead doping on the microstructure and visible light photocatalysis of bismuth titanate prepared by the oxidant peroxide method (OPM)

Abstract

Pure (Bi<inf>12</inf>TiO<inf>20</inf>) and La- and Pb-doped (Bi<inf>12-x</inf>La<inf>x</inf>TiO<inf>20</inf> e Bi<inf>12-x</inf>Pb<inf>x</inf>TiO<inf>20</inf>, with x up to 1.50) bismuth titanates were prepared by the oxidant peroxide method (OPM) and used for photodegradation of rhodamine b (RhB). The synthesized materials samples were characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectra (DRS), X-ray photoluminescence (PL) spectroscopy, scanning electron microscopy (SEM), X-ray fluorescence (XRF) and N<inf>2</inf> physical adsorption. Rietveld refinements showed samples consisting mainly of sillenite structure with small amounts of a perovskite secondary phase in the La- and Pb-doped materials. The photocatalytic properties of all materials were evaluated by the discoloration of RhB solution under ultraviolet (UV) and visible irradiation, where the bismuth titanate obtained by the OPM route showed higher photocatalytic activity than the commercial TiO<inf>2</inf>. Furthermore, it was observed that the insertion of different ions in the bismuth titanate structure changes the band gap energy in different ways, which consequently altered the photocatalytic activities of the materials.