Photocatalytic Degradation of Methylene Blue Using Iron Doped Tio2 Porous Shell under Light Irradiation
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Date
2021-09
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Addis Ababa University
Abstract
Titanium dioxide is a well-known photocatalyst for the photodegradation of dyes like methylene blue. However, its application is limited due to its wide bandgap and higher recombination rate of photogenerated electrons and holes. This work shows that doping transition metals lead to reducing the bandgap and increasing surface area to improve the degradation efficiency of titanium dioxide (TiO2). Iron doped TiO2 hollow and porous spheres with different Fe-doping contents were prepared based on a sol-gel synthesis. Melamine formaldehyde (MF) has been used as a sacrificial template, and cetyltrimethylammonium bromide (CTAB) was used as a pore-directing agent. By calcining the composite spheres at 450, 500, 550 ◦C for three h in air, and in situ Fe doped TiO2 hollow and porous spheres process occurred upon the decomposition of the MF template and CTAB pore-directing surfactant. The 0.25wt% Fe-doped porous TiO2 hollow nanosphere at 450oC exhibited a significantly narrower optical bandgap and higher photocatalytic activity in the removal of Methylene blue (MB) than that of the pure THPNS. The composition and Fe-doping content, thermal stability, morphology, surface area, and pore size distribution, photocatalytic activities, and optical properties of the porous TiO2 hollow spheres derived from different conditions were investigated and compared based on X-ray diffraction (XRD), Fourier-transformation infrared ray spectroscopy (FT-IR), Scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET) Thermogravimetric analysis (TGA/DTA), Diffuse reflection spectroscopy (DRS analysis), Zeta sizer, and Ultraviolet-Visible (Uv-Vis) Spectroscopy techniques. The effect of dye concentration, dopant concentration, pH of the dye solution, catalyst loading, and calcination temperature on the characteristics, photocatalytic activities, and optical properties of the hollow and porous TiO2 Nanosphere has been studied and discussed.
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Keywords
Titanium dioxide, Fe dopant, Hollow and Porous sphere morphology, Photocatalyst