Abstract
•Hollow carbon fibers derived from natural cotton was successfully prepared by pyrolysis method.•TiO2 nanorods immobilized on carbon fibers by a facile hydrothermal method showed high photocatalytic activity.•The enhancement was due to the reduced band gap, improved dye adsorption capacity and effective electron–hole separation.
In this study, TiO2 nanorods were successfully immobilized on carbon fibers by a facile pyrolysis of natural cotton in nitrogen atmosphere followed by a one-pot hydrothermal method. Carbonized cotton fibers (CCFs) and TiO2-CCFs composites were characterized using field-emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, X-ray diffractometer (XRD), diffuse reflectance UV–vis spectroscopy (DRS) and photoluminescence (PL) spectroscopy. Results implied that the band gap narrowing of TiO2 was achieved after integration of CCFs. Dye adsorption isotherm indicated that the maximum dye adsorption capacity (qm) of CCFs-1000 (13.4mg/g) was 2 times higher than that of cotton fibers and qm of TiO2-CCFs-1000 (9.0mg/g) was 6–7 times higher than that of TiO2 nanorods. Photocatalytic activity of TiO2 nanorods prepared with 3mL Ti(OBu)4 showed the highest photocatalytic activity. TiO2-CCFs-1000 exhibited higher activity than TiO2 immobilized on CCFs-400, CCFs-600 and CCFs-800. Good photostability of TiO2-CCFs-1000 was found for dye degradation under visible light irradiation. The enhancement of photocatalytic dye degradation was due to the high adsorptivity of dye molecules, enhanced light adsorption and effective separation of electron–hole pairs. This work provides a low-cost and sustainable approach to immobilize nanostructured TiO2 on carbon fibers for environmental remediation.