Photocatalytic mechanism and properties of recyclable hybrid magnetic/semiconductor nanocomposites synthesized via green route for organic dye degradation

Abstract

The investigation of the efficiency of recycling, rapid separation, high catalytic performance of photocatalyst materials, and the properties of the material after the photocatalytic process (after use) are considered important for photodegradation applications. Green-synthesized hybrid magnetic/semiconductor nanocomposites utilizing Moringa oleifera leaf extract exhibit excellent photocatalytic performance and reusability under ultraviolet (UV) irradiation. In this study, CoFe2O4/TiO2 nanocomposites were investigated as magnetic/semiconductor photocatalysts. The properties of the green-synthesized nanocomposites before and after the photocatalytic process (recycled photocatalyst) were investigated using UV–visible spectroscopy, X-ray diffraction, transmission electron microscopy, scanning electron microscopy–energy dispersive X-ray spectroscopy, X-ray fluorescence, Fourier transform infrared spectroscopy, and vibration sample magnetometry. The optical bandgap energies before and after the formation of the nanocomposites were 3.8 and 3.9 eV, respectively. The typical organic pollutant methylene blue was completely degraded within 2 h with an efficiency of 97.4% using the nanocomposites. The crystallite sizes of the nanocomposites before and after use were 11.1 and 10.5 nm, respectively. The magnetic hysteresis curve also showed that, after use, the nanocomposites had a saturation magnetization of 10.6 emu/g and coercivity of 90 Oe. The optical properties, crystal structures, magnetic properties, and morphologies indicated that the nanocomposites were the same as the prepared nanocomposites and retained the same photocatalytic ability after use. Hence, it can be concluded that the green-synthesized hybrid magnetic/semiconductor nanocomposites deliver excellent catalytic performance, and we believe that our findings provide a new platform for efficient photocatalytic applications.