Functional Materials with Wide-Spectral-Responsive Photocatalytic Activity and Real-Time Temperature Feedback: The Electrospun Fibers Embedded with NaGdF4-Tm-Yb@TiO2 Nanocrystals

In this work, combining the advantages of upconversion materials, nanofibers, and TiO2 semiconductors, the composite fibers embedded with NaGdF4: Tm3+, Yb3+@TiO2 nanocrystals (NGF-TY@TiO2 NCs) are prepared as wide-spectral (UV-NIR) response photocatalysts and temperature sensing materials. Based on the FIR technique, both the thermally (F-3(2,3) and H-3(4)) and nonthermally ((1)G(4) and F-3(2,3)) coupled levels of Tm3+ are confirmed to be applicable as temperature probes for real-time monitoring and feedback of the working temperature of the catalytic degradation process, and the maximum relative sensitivity values of S-R1 and S-R2 are as high as 2.760%K-1 and 3.019%K-1 at 304 K, respectively. Under 977 nm laser excitation, the energy migration from NGF-T0.4Y6 to TiO2 is demonstrated to a fluorescence resonance energy transfer process. The degradation ratio of rhodamine B (RhB) is 19.3% in the presence of NGF-T0.4Y6@TiO2/PAN fibers and the degradation constant K reaches 0.00117 min(-1) after 3 h irradiating from Xe lamp with a UV cutoff filter. Accordingly, this study suggests a new perspective to utilize the NIR energy of sunlight for photocatalytic application based on TiO2, and the addition of dual temperature feedback provides a reliable reference for the development of safer and more efficient catalytic materials.