Hydrothermal synthesis of BiOBr/FeWO4 composite photocatalysts and their photocatalytic degradation of doxycycline

Highlights: • The microsphere structures BiOBr/FeWO₄ were successfully fabricated. • The addition of FeWO₄ reduced the band gap energy of BiOBr. • BiOBr/FeWO₄ exhibited superior photodegradation in doxycycline. • BiOBr/FeWO₄ promoted the separation of electron-hole pairs. Novel BiOBr/FeWO₄ composite photocatalysts were fabricated using the solvothermal method to degrade doxycycline under visible light irradiation. The crystalline structures, morphology, chemical composition, chemical bonding, energy band gap and photocatalytic properties of the samples were characterized by XRD, SEM, TEM, EDS, XPS, FT-IR and UV-Vis DRS. The BiOBr/FeWO₄ composite photocatalysts with different molar mass ratios exhibited higher photocatalytic degradation efficiency of doxycycline than pure BiOBr and FeWO₄, and the best photocatalytic degradation performance of 90% in 1 h was found for BiOBr/FeWO₄ (4:1). XPS and FT-IR analyses revealed the elemental composition, corresponding hybrid orbitals and possible chemical bonds. The DRS results indicated that FeWO₄ enhanced the light response range of BiOBr. The generation of O₂⁻ and holes was promoted by inhibiting the recombination of photogenerated carriers, which could lead to the higher photocatalytic activity.