Construction of SrTiO3/Bi2O3 heterojunction towards to improved separation efficiency of charge carriers and photocatalytic activity under visible light

Abstract

In this paper, the novel SrTiO3/Bi2O3 heterostructures photocatalysts were fabricated by a facile microwave process, and the visible-light-driven photocatalytic activity has been investigated for tetracycline (TC) degradation. The as-synthesized of SrTiO3/Bi2O3 photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–vis diffuse reflection spectroscopy (DRS). The photocatalytic performance was evaluated by the degradation TC under visible light irradiation (λ > 420 nm). Compared to pristine SrTiO3 and Bi2O3, the as-prepared SrTiO3/Bi2O3 samples exhibited remarkably enhancing photocatalytic activity for degradation of TC. It was found that the 50% SrTiO3/Bi2O3 heterojunction showed the highest photocatalytic efficiency for TC degradation, and the degradation rate could reach 85% in 140 min. The enhanced photocatalytic activity was attributed to the formation of a heterojunction between SrTiO3 and Bi2O3, which could greatly improve the transfer and separation of charge carriers in the two-phase interface. Meanwhile trapping experiments indicated that the h+ and OH were the main active species.