Cu/TiO2 composite nanofibers with improved photocatalytic performance under UV and UV–visible light irradiation

This is the first-time report on the optimization of pure TiO2 and Cu/TiO2 nanocomposite photocatalytic fibrous materials fabricated by electrospinning followed by removal of the organic components by calcination at high temperature. Morphological investigations of the fabricated nanocomposites performed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were supported with spectroscopic investigations via X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy, ultraviolet–visible spectroscopy (UV–Vis) and photoluminescence (PL) spectroscopy. These findings clearly indicate that the copper presence into TiO2 lattice triggers the sunlight-driven photocatalysis, as compared to pure TiO2 that use the ultraviolet light to achieve the photoactivation. As a result, remarkable photocatalytic activity on the degradation of Amaranth dye was obtained. The maximum color removal efficiency of 99.84% was observed for the degradation of Amaranth dye for an initial concentration of 25 mg/L, after 240 min of Vis-light irradiation. Excellent results were obtained for the case of 0.05%Cu/TiO2 nanocomposite (calcinated at 400 °C) that yielded to a maximum value for the constant rate (k = 2.089 × 10−2 min−1). As compared to the undoped material (TiO2/400 °C), the 0.05%Cu/TiO2 nanocomposite led an almost double reaction rate (the constant rate increasing from 1.015 × 10−2 to 2.089 × 10−2 min−1). In addition, the 0.05%Cu/TiO2 nanocomposite calcinated at 400 °C was tested for the degradation of Amaranth dye under visible-light irradiation. Thus, at catalyst doses of 0.4 to 0.8 g/L, the reaction rate constant attained the order of 10−2 min−1 under visible irradiation. These results are outstanding when compared with previously reported works.