Photocatalytic Properties of Hollow BiFeO3 Spheres

Resumo

Single-phase hollow bismuth ferrite microspheres ∼1 µm in diameter were synthesized by ultrasonic spray pyrolysis in a stream of air or argon. All the samples exhibited photocatalytic activity exceeding that of the standard TiO₂ catalyst under UV irradiation. The samples synthesized in an argon stream exhibit catalytic activity under irradiation with a blue light. A comprehensive study showed that the appearance of the catalytic activity under the action of visible light was not associated with the powder particle morphology, oxygen defectiveness, and a change in the band gap width. An X-ray photoelectron spectroscopic study revealed decreased content of adsorbed oxygen on the surface of BiFeO₃ synthesized in an argon stream. Possible mechanisms responsible for the appearance of the photocatalytic activity in the visible range are discussed.