α-Fe2O3/ZnO nanocomposite as an efficient photocatalyst for wastewater treatment and flexible electronic device applications

In this work, we report the synthesis of alpha-Fe2O3, ZnO, and alpha-Fe2O3/ZnO nanomaterials by a simple sol-gel method for photocatalytic dye degradation and flexible electronic applications. X-ray diffraction results reveal that the synthesized samples were rhombohedral and hexagonal wurtzite structures of alpha-Fe2O3, and ZnO nanoparticles, respectively. alpha-Fe2O3/ZnO composites exhibit the mixed peaks of both alpha-Fe2O3 and ZnO crystal structures which substantiate the formation of alpha-Fe2O3/ZnO composites. From the optical studies, the band gaps of alpha-Fe2O3, ZnO, and alpha-Fe2O3/ZnO composites of (1:1) and (1:2) ratios are calculated as 2.11, 3.14, 2.87, and 2.92 eV respectively. Compared to pure alpha-Fe2O3 and pure ZnO nanoparticles, alpha-Fe2O3/ZnO composites of (1:2) ratio exhibit superior photocatalytic behavior under the irradiation of the natural sunlight and also show good stability for up to five cycles. From the scavenger studies, it is concluded that hydroxyl radicals are the major contributors to the photocatalytic degradation of methylene blue dye molecules. The dielectric behavior of the pure and blended nanoparticles is also investigated in a wide range of frequencies using impedance spectroscopy. The nanoparticles embedded in polyvinyl alcohol (PVA) or alpha-Fe2O3/ZnO/PVA thin films demonstrate a higher dielectric constant (32.68) and lower loss factor (3.32) than pristine PVA. The AC conductivity (sigma(AC)) of alpha-Fe2O3/ZnO composites of (1:2) ratio is 10(-12) S/cm. These findings indicate the possibilities of using alpha-Fe2O3/ZnO/PVA composites for the fabrication of flexible electronic devices.