Synthesis of γ-Fe2O3/La/Bi2WO6 composites for enhanced visible light-driven photocatalytic degradation of tetracycline hydrochloride.

Abstract

γ-Fe2O3/La/Bi2WO6 heterojunction composites have been successfully synthesized by simple and convenient hydrothermal method. The photocatalytic activity of the prepared samples was evaluated by the degradation of tetracycline hydrochloride (TCH) solution under simulated visible light irradiation. The results indicated that the removal rate of γ-Fe2O3/La/Bi2WO6 samples was higher than that of pure Bi2WO6 and La/Bi2WO6, among which 5%γ-Fe2O3/La/Bi2WO6 had the highest photocatalytic activity. The removal rate of TCH solution can reach 92.42% in 220min. The as-prepared samples were characterized by scanning electron microscope (SEM), Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), and UV-vis diffuse reflectance spectrum (DRS). The material morphology of γ-Fe2O3/La/Bi2WO6 was nano-flake. γ-Fe2O3/La-doped Bi2WO6 did not damage the crystal phase and structure of Bi2WO6. Through getting insight into the mechanism, γ-Fe2O3/La doping increased the specific surface area of Bi2WO6 and inhibited the recombination of photogenerated electron pairs, thus enhancing the photocatalytic activity. h+ and ·O2- were the main active substances in the photocatalytic degradation of TCH solution by γ-Fe2O3/La/Bi2WO6 photocatalysts. In order to better explain the photocatalytic degradation process of TCH solution by γ-Fe2O3/La/Bi2WO6 photocatalyst, a possible removal mechanism was proposed for the first time. Moreover, γ-Fe2O3/La/Bi2WO6 sample is magnetic and easy to recover. At the same time, the high stability of γ-Fe2O3/La/Bi2WO6 sample can be reused.