Recyclable and flexible Bi(Ho-Yb)OBr/g-CN composite porous fiber for efficient water purification and real-time temperature sensing.

Herein, an electrospinning porous nanofiber with large specific surface area, excellent flexibility, remarkable tensile strength, and high stability of thermal degradation has been developed by loading Ho/Yb co-doped BiOBr/g-CN (BHY/CN) heterojunction photocatalysts on polyacrylonitrile (PAN) nanofibers. The optimized BHY/CN-2 nanofiber demonstrates outstanding photocatalytic activity for the degradation of 98.83% tetracycline (TC, 60 min) and 99.06% rhodamine B (RhB, 90 min) under simulated sunlight irradiation, and maintains a high level of reusability and recycling stability in three cycles. In addition, temperature monitoring of the catalytic degradation process can be feedback by (F, S) → I and F → I radiation transitions of Ho with excellent sensitivity. More importantly, the nanofiber luminescence performance is enhanced by the doping of g-CN, which maintain the effective upconversion luminescence properties even in water, providing a reliable reference for real-time monitoring and feedback of the operating temperature, and further expanding the application fields of photocatalysts.