Comparative Study on the Role of Noble Metal Nanoparticles (Pt and Pd) on the Photocatalytic Performance of the BaFe12O19/TiO2 Magnetic Nanocomposite: Green Synthesis, Characterization, and Removal of Organic Dyes under Visible Light

Adding noble metals and barium hexaferrite to TiO2 creates novel magnetic plasmonic nanocomposites with high activity in the photodegradation of organic contaminants. In this work, we have synthesized BaFe12O19 by microwave and sol-gel combustion (using green fuel, glucose) methods and TiO2 by the sol-gel method. Then, noble metals (Pt and Pd) were deposited on BaFe12O19/TiO2 by a reducing agent (glucose: green surfactant) under ultrasound waves. The samples were characterized. On the basis of XRD and SEM results, the composites are highly crystalline and impurity-free. TEM images and BET analysis indicated the samples have a suitable morphology. Furthermore, the magnetic analysis showed the addition of TiO2 and noble metals to barium hexaferrite has led to the lower coercivity, but the synthesized nanocomposites still have the suitable magnetic properties (M-s(BaFe12O19/TiO2@Pt) = 37, M-s(BaFe12O19/TiO2/Pd) = 34, M-r(BaFe12O19/TiO2@Pt) = 16, M-r(BaFe12O19/TiO2/Pd) = 13.9 emu/g). UV-vis DRS spectra revealed the band gaps of BaFe12O19/TiO2@Pt and BaFe12O19/TiO2/Pd are 3.13 and 3.08 eV, respectively. Finally, BaFe12O19/TiO2@Pt and BaFe12O19/TiO2/Pd nanocomposites were used to degrade the anionic and cationic dyes under visible irradiation within 120 min. The highest percentage of degradation was related to methyl orange, around 96% and 92% by BaFe12O19/TiO2@Pt and BaFe12O19/TiO2/Pd, respectively. Indeed, Pt because of its high work function and electron affinity is more effective in photodegradation.