Fabrication of Au functionalized TiO₂ nanofibers for photocatalytic application

Pristine titanium dioxide (TiO₂) and gold (Au)-doped TiO₂ (TiO₂–Au) composite nanofibers (NFs) with different Au contents were fabricated by electrospinning. The thermal behavior of the as-spun composite precursor NFs were analyzed and characterized. Photocatalytic reactions were performed with methyl blue (MB) aqueous solution under UV–Vis and different irradiation wavelengths (including 360 nm, 528 nm, and 360 nm and 528 nm together). As a result, the morphology and the structure of TiO₂–Au composite NFs were significantly influenced by calcination temperature, leading to the controllable phase ratio of anatase and rutile in TiO₂. TiO₂–Au composite NFs, with an average diameter of 171 nm containing Au crystals of about 10 nm, exhibited enhanced photocatalytic efficiency toward the MB, compared to that of commercial P25 (a multiphase TiO₂ 98% anatase and 2% rutile). The corresponding degradation level reached 95% after 10 min. When irradiated with light having different wavelengths, the TiO₂–Au composite NFs catalyst had the best performance under 360 nm and 528 nm together, indicating that Au NPs functionalized TiO₂ NFs can enhance the photocatalysis from UV range to visible range. The mechanism of photocatalytic reactions under different irradiations is discussed in the present paper.