Photo-reduced TiO2@WO3 electrospun nanofibers for efficient SERS and photoelectrochemical performances

Semiconductor-based Surface-enhanced Raman spectroscopy (SERS) specified for detecting pollutants is highly desired owing to the increasing demand for environmental monitoring and chemical analysis. Herein, we prepared a bifunctional and photo-reduced TiO2@WO3 membrane using combined electrospinning, hydrothermal and subsequent UV-irradiation. The photo-reduced TiO2@WO3 nanofibers (∼5 min UV irradiation) exhibited promising detection performance, gaving a 7-fold enhancement in free carrier concentration (1.52 × 1021 cm−3), compared with TiO2@WO3 nanofibers and approaching the level of noble metals (2.5 × 1022 cm−3). For the photo-reduced TiO2@WO3 nanofibers (∼15 min UV irradiation), the SERS enhancement factor can be further increased to 2.45 × 105 and the limit of detection was as low as 10−9 M. Its photoelectric properties were also investigated and results were pretty good owing to the enhanced charge transfer and increased carrier density by UV irradiation. Such a simple and low-cost fabrication method for functional membranes holds great promise for practical applications.