Fabrication of CuBi2O4/Bi2MoO6 p-n heterojunction as synergistic photoelectric catalyst for efficient removal of ciprofloxacin in photo-electro-Fenton-like system

Ciprofloxacin (CIP) has been widely detected in aquatic ecosystems due to antibiotics abuse and its refractory, which seriously affected public health and ecological safety. Herein, we devised a photo-electro-Fenton-like (PEF-like) system for efficient removal of CIP. CuBi2O4/Bi2MoO6 (CBMO) p-n heterojunction composites were successfully fabricated through hydrothermal and solvothermal methods. Significantly, CBMO composite cata-lysts were not only able to generate center dot OH by the Cu+ activation of H2O2 during electro-Fenton process, the following synergistic effects in the photo-Fenton process simultaneously promoted the production of more center dot OH. The internal electric field (IEF) in the p-n heterojunction was conducive to the directional transfer of photo -generated electrons, thus promoting the spatial separation of photogenerated carriers. Moreover, photogenerated electrons could directly or indirectly activate H2O2 to yield more abundant center dot OH, thus improving photoelectric catalytic activity. Consequently, the degradation efficiency of CIP during PEF-like system was 97.4% in 90 min and the mineralization efficiency finally reached 78.5% in 180 min. The prepared CuBi2O4/Bi2MoO6-40 (CBMO-40) possessed great stability and structural integrity after six consecutive cycles. Furthermore, the CBMO-40 in PEF-like system showed superior performance for the removal of diverse antibiotics, including quinolones, tet-racyclines and sulfonamides, which revealed the broad applicability of CBMO-40 for the antibiotics removal in PEF-like system.