Efficient photocatalytic degradation of gaseous formaldehyde by the TiO2/tourmaline composites

The TiO2 supported tourmaline composites were prepared by a sol–gel method and used as a photocatalyst for the degradation of formaldehyde (HCHO). The composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), N2 adsorption–desorption, Fourier transform infrared (FT-IR) spectroscopy and UV–vis diffuse reflectance spectroscopy (UV–vis DRS). The results indicate that the mixed-phase of anatase and rutile exists in the TiO2/tourmaline composites. The specific surface area of the TiO2/tourmaline composites is much higher than that of the pure TiO2. The TiO2/tourmaline composites exhibited excellent photocatalytic activity for the degradation of HCHO, which was 6 times higher than that of the pure TiO2. Moreover, the excellent photocatalytic activity of the composites was fully maintained after five photocatalytic cycles, which may be attributed to the physicochemical property of tourmaline and the mixed-phase of anatase and rutile in the TiO2/tourmaline composites.