The residues of daily-used antibiotics are difficult to be removed and very harmful to the environment. Herein, FeO@FeP heterostructure was constructed by surface phosphorization of hematite (α-Fe₂O₃) synthesized via a facile hydrothermal method for efficient photo-Fenton degradation of antibiotic norfloxacin (NOR). Compared with the bare α-Fe₂O₃, the FeO@FeP heterostructure exhibits much-enhanced photocatalytic Fenton-like performance, with NOR degraded by 75% within 5 ​min by sunlight-driven photo-Fenton reactions. It was suggested that the surface phosphorization-derived metallic FeP overlayer could accelerate the separation and migration of photogenerated charge carriers in α-Fe₂O₃, which benefits the generation of •OH and O₂^•− reactive radicals from photo-Fenton reaction and thus give rise to the great enhancement in NOR degradation activity. This study displays an alternative strategy of surface engineering to design novel heterostructured materials for the efficient photo-Fenton treatment of wastewater containing antibiotic residues as well as other organic pollutants.

Photodynamic therapy (PDT), which is a procedure that uses photosensitizing drug to apply therapy selectively to target sites, has been proven to be a safe treatment for cancers and conditions that may develop into cancers. Nano-sized TiO₂ has been regarded as potential photosensitizer for UV light driven PDT. In this study, four types of TiO₂ nanofibers were prepared from proton tri-titanate (H₂T₃O₇) nanofiber. The as-obtained nanofibers were demonstrated as efficient photosensitizers for PDT killing of HeLa cells. MTT assay and flow cytometry (FCM) were carried out to evaluate the biocompatibility, percentage of apoptotic cells, and cell viability. The non-cytotoxicity of the as-prepared TiO₂ nanofibers in the absence of UV irradiation has also been demonstrated. Under UV light irradiation, the TiO₂ nanofibers, particularly the mixed phase nanofibers, displayed much higher cell-killing efficiency than Pirarubicin (THP), which is a common drug to induce the apoptosis of HeLa cells. We ascribe the high cellkilling efficiency of the mixed phase nanofibers to the bandgap edge match and stable interface between TiO₂(B) and anatase phases in a single nanofiber, which can inhibit the recombination of the photogenerated electrons and holes. This promotes the charge separation and transfer processes and can produce more reactive oxygen species (ROS) that are responsible for the killing of HeLa cells.