Influence of iron doping on the photocatalytic activity of nanocrystalline TiO₂ particles fabricated by ultrasound method for enhanced degradation of organic dye

Abstract

Synthesis and characterization of Fe doped TiO₂ composite with iron concentration varying from 0 to 7% as a photocatalyst in the photodegradation of methylene orange on UV–Vis light irradiation in a closed reactor has been carried out. Synthesis was conducted by the ultrasound method at room temperature using tetrabutyl titanate and iron(III)chloride 6-hydrate as a precursor, followed by thermal treatment at a temperature of 600 °C. The characterizations were performed using X-ray diffraction (XRD), transmission electron microscopy, scanning electron microscopy (SEM), FT-IR spectrometry, thermal analysis, UV–Vis diffuse reflectance spectrophotometer, photoluminescence and Brunauer–Emmett–Teller (BET). XRD spectra revealed that samples crystallized in the anatase phase at 600 °C. The transmission and SEM were used to detect the morphology of synthesized nanoparticles, which sizes changed with the altitude in the doping concentration to 7%. FTIR spectra exhibit broad peaks where anatase phases of TiO₂ demonstrate very sharp peaks. In accordance with UV–Vis absorption measurements, this diminution of nanoparticles sizes was followed by a decrease in the band gap value from 3.21 eV, for undoped TiO₂, to 2.46 eV, for TiO₂ doped at 7%. The TGA showed three mass losses, whereas DTA resulted in three endothermic peaks. The maximum photoconversion efficiency was 2.5%, which was six times the photoconversion efficiency of undoped TiO₂. Finally, the prepared materials were used to photocatalyse the decolourization of methylene orange in aqueous medium as a model compound under the illumination of visible light (λ = 420 nm).