A flower-like metallic Bi-modified Bi2WO6/BiOI heterojunction was fabricated by a two-step approach of hydrothermal method and in situ ethylene glycol reduction method. The ternary system was confirmed by structural analysis and surface and morphological studies. Compared with Bi2WO6, BiOI, and their binary nanomaterials, the catalyst exhibits excellent photocatalytic performance for the degradation of ciprofloxacin (CIP) and levofloxacin (LEV) under visible light irradiation. The improvement of photocatalytic performance was ascribed to the synergistic effect between metal Bi nanoparticles and Bi2WO6/BiOI p-n heterojunction, which enhanced the light absorption capacity and the separation efficiency of photogenerated carriers. By studying the effect of solution pH on CIP degradation, it was found that when pH = 10 , the degradation efficiency of the catalyst on ciprofloxacin reached 100% within 40 min. It provides a new idea for the design and synthesis of ternary photocatalysts for purification of alkaline domestic sewage.

A Bi-BiOBr/BiPO4 heterojunction structure was successfully synthesized via a two-step solvothermal method with ethylene glycol as a reducer. Little BiPO4 irregular polyhedrons and little metal Bi spherical nanoparticles were uniformly dispersed on the surface of BiOBr nanosheets with intimate contact and formed a heterojunction structure between BiPO4 and BiOBr. It was found that Bi-BiOBr/BiPO4 had a significant improvement in photocatalytic performance for RhB degradation compared to bare BiOBr and BiPO4. The photocatalytic degradation rate constant of 0.2-Bi/BiOBr/BiPO4 was 1.44 h-1, which was 3.8 times and 14.2 times more than that of bare BiOBr and BiPO4, respectively. This is attributed to the formation of a ternary heterojunction, which benefits the separation of photogenerated electron-hole pairs. Furthermore, with the introduction of metal Bi, the SPR effect of metal Bi can effectively improve the absorption ability of Bi-BiOBr/BiPO4 photocatalyst, resulting in enhanced photoactivity. In this work, the mechanism of photocatalytic degradation was studied by using the photochemical technique and the capture experiment of active species, and it was revealed that h+ and ⋅O2- played a major role in the photocatalytic process.