Enhanced photocatalytic activity of Eu-doped Bi2S3 nanoflowers for degradation of organic pollutants under visible light illumination

Abstract

Europium (Eu)-doped Bi₂S₃ nanoparticles (NPs) with different Eu contents were successfully synthesized by solvothermal decomposition of the precursor complexes Bi(ACDA)₃ and [Eu(ACDA)₃·H₂O] [ACDA = 2-aminocyclopentene-1-dithiocarboxylic acid] in ethylenediamine (EN). The precursors were characterized by usual techniques such as UV-vis and FT-IR spectroscopy, and CHN and TGA analyses. The prepared nanomaterials were characterized by XRD, EDX, SEM and TEM analyses. The XRD results demonstrate that the particles were highly crystallized. The TEM images ascertain the NPs to be of flower-like structure consisting of ultrathin nanoplates with an average diameter of 9–10 nm. Photocatalytic efficiency of the Eu-doped Bi₂S₃ NPs was evaluated by monitoring the degradation of methylene blue (MB) in aqueous solution under visible light. It was observed that the rate of photocatalytic degradation of MB increases with an increase in the amount of the dopant ion. In addition, the photocatalytic degradation of various toxic organic pollutants such as phenol, p-cresol, 4-chlorophenol, 4-tert-butylphenol, 2,5-dimethylphenol and 2,6-di-tert-butyl-p-cresol was carried out with doped NPs in visible light. Under identical conditions, the degradation rate of 4-chlorophenol is higher than the corresponding phenol, p-cresol and 4-tert-butylphenol. Finally, the mechanism of the degradation pathway for phenol and the substituted phenols is discussed.