Flexible Bi(Er³⁺/Yb³⁺)₂MoO₆/PAN with sensitive temperature feedback and enhanced visible light photocatalysis

(Bi_1-x-yEr_xYb_y)₂MoO₆ polyacrylonitrile (BMO-EY/PAN) is fabricated with nanocrystal-inlaid fiber structure via electrospinning, which fulfills efficient photocatalytic performance and real-time temperature monitoring. In comparison to their conventional powdered BMO counterparts, embedding BMO-EY nanocrystals into the PAN polymer imparts a suite of desirable traits to the fibers, such as efficient solar energy utilization, outstanding reproducibility, superior stretchability (498 cN), and extensive specific surface area (24.11 m² g⁻¹). The working temperature of the catalytic degradation process is monitored and fed back in real time by ²H_11/2 → ⁴I_15/2 and ⁴S_3/2 → ⁴I_15/2 radiation transitions of Er³⁺ with excellent sensitivity. Simultaneously, the addition of rare earth (REs) elements into the bismuth molybdate lattice broadens its visible absorption range, expediting charge transfer of photogenerated electrons and augmenting its ability to degrade pollutants under visible light irradiation. The degradation efficiency of tetracycline hydrochloride (TCH) reaches a maximum of 97%, while the degradation constant K is notably high at 0.047 min⁻¹ when subjected to simulated sunlight irradiation. This degradation trend is also observed in the case of rhodamine B (RhB). In general, these advanced photocatalytic fibers, equipped with non-contact temperature feedback capabilities, manifests the potential to serve as an effective, cost-efficient, and environmentally sustainable approach for water treatment processes.