Synthesis and comparison of photocatalytic activity under UV–Visible or visible light irradiation for Bi3TaO7 and Bi2YTaO7 photocatalysts

Abstract

The synthesis and photocatalytic activity of Bi3TaO7 and Bi2YTaO7 were reported in this work. Bi3TaO7 and Bi2YTaO7 nanowires with a cubic phase were synthesized by a solvothermal method. Under ultraviolet–visible (UV–Vis) or visible light irradiation, Bi3TaO7 and Bi2YTaO7 nanowires show excellently photocatalytic activities for rhodamine B (RhB) and methyl orange (MO). The electron spin resonance measurements demonstrate that ·OH and ·O2− radicals are responsible for the degradation of RhB and MO. The formation of ·O2− is induced by the defect fluorite-type structure with distorted octahedral coordination geometry for Bi3TaO7, which exhibit intrinsic oxygen vacancies and disorders in both anionic and cationic lattices. The UV–Vis diffuse reflectance spectra reflect that Bi2YTaO7 has lower band gap energy than that of Bi3TaO7. Due to the lower band gap energy and the special 4f electron configuration of Y3+, Bi2YTaO7 shows higher photocatalytic activity than that of Bi3TaO7.