Preparation, characterization, and photocatalytic activity evaluation of Fe-N-codoped TiO₂/fly ash cenospheres...

Nitrogen-doped titanium dioxide (TiO₂) and Fe-N-codoped TiO₂ layers on fly ash cenospheres (FAC) as floating photocatalyst were successfully prepared through sol-gel method. Photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet (UV)-Vis diffuse reflectance spectroscopy (DRS), and nitrogen adsorption analyses for Brunauer-Emmett-Teller (BET) specific surface area. Photocatalytic efficiency of the prepared catalyst was evaluated through using the decomposition of Rhodamine B (RhB) as a model compound under visible light irradiation. Photocatalytic activity and kinetics of catalyst under visible light were detected in details from different Fe/Ti mole ratios by detecting photodegradation of RhB. Experimental results show that when the calcination temperature was 550 °C, the dosage of FAC was 3.0 g, and the mole ratio of Fe/Ti was 0.71 %; the synthesized Fe-N-TiO₂/FAC photocatalyst presented as anatase phase and that N and Fe ions were doped into TiO₂ lattice. The material's specific surface area was 34.027 m²/g, and UV-Vis diffuse reflectance spectroscopy shows that the edge of the photon absorption has been red shifted up to 400-500 nm. Fe-N-codoped titanium dioxide on FAC had excellent photocatalytic activity during the process of photodegradation of RhB under visible light irradiation.