A facile synthesis for uniform tablet-like TiO2/C derived from Materials of Institut Lavoisier-125(Ti) (MIL-125(Ti)) and their enhanced visible light-driven photodegradation of tetracycline.

The uniform tablet-like TiO2/C nanocomposites with two crystal types (rutile and anatase) and large specific surface area (438 m2 g-1) were successfully prepared by Materials of Institut Lavoisier-125(Ti) (MIL-125(Ti)) calcined at a suitable temperature and applied for photocatalytic tetracycline (TC). The nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and mapping, N2 adsorption-desorption isotherms, photoluminescence spectra (PL), photocurrent, and X-ray photoelectron spectroscopy (XPS). The changes of physicochemical parameters are discussed in detail. It is found that nanocomposite through suitable calcination temperature (M-A-800) with large surface area and appropriate micropore/mesopore ratio could strengthen separation and migration rates of photo-generated charge, resulting in the improvement of visible light photocatalytic activity of tetracycline, and exhibited about 2.0 times quicker than that of MIL-125(Ti). In addition, M-A-800 displayed favourable reusability and stability in four circulation tests. Finally, the reaction mechanism of photocatalyst and photodegradation pathway of tetracycline was also proposed. O2- was the most important active species, and dehydroxylation and decarboxylation were the main photodegradation pathway of tetracycline.