Synthesis of mesoporous titania–graphite composite templated by hypocrellins for visible-light photocatalytic degradation of acetaldehyde

Abstract A photoactive compound extracted from a fungus ( Hypocrella bambuase ), named hypocrellins, was used as template to synthesize thermally stable mesoporous materials. The synthesized mesoporous titania samples were characterized using a combination of various physicochemical techniques, such as N 2 adsorption/desorption measurement, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS) and Fourier transform infrared spectroscopy (FT-IR). The results of physicochemical characterizations showed that the as-synthesized sample was a composite of highly crystalline mesoporous anatase titania and graphitic carbon (gc–MTiO 2 ), which implies the dual function of hypocrellins as template and “dopant”. The in situ doped graphitic carbon significantly increased the visible-light absorbance of TiO 2 . The gc–MTiO 2 exhibited efficient photocatalytic activity under visible-light for photodegradation of acetaldehyde, a common indoor air pollutant. The photophysics and electron dynamics in this photocatalytic process were studied by time-resolved FT-IR spectra, in particular on the nano- to milli-second time scale. It is observed that electrons were injected into the conduction band of gc–MTiO 2 and they were decayed to deep traps caused by graphitic carbon. The reported strategies could open up new uses for mesoporous titania self-doped with carbon in applications such as solar cells, photocatalysts, photoelectrical devices, and photo-induced sensors.