Interstitial incorporation of Fe³⁺ and Fe²⁺ into ZnO crystal lattice: tailoring their physical properties for spintronics and photocatalytic applications

Abstract Mixing of industrial waste water effluents with fresh water reservoirs without prior removal of pollutants is major cause of concern for healthy aquatic life. Therefore, remediation of pollutants in waste water by suitable photocatalyst is an interesting area to alleviate water pollution. Many photocatalyst have been designed recently but there is still gap to synthesize the optimized energy bandgap material with high efficiency to degrade organic dyes in shortest time. Hence, sunlight driven doped ZnO materials, i.e., Zn 1−x Fe x O (x = 0, 0.02, 0.04, and 0.06) photocatalysts were designed. The effect of Fe concentration on the structural, morphological, optical, electrical, and magnetic properties was studied. The hexagon-shaped wurtzite structure of ZnO NPs was verified by the x-ray Diffraction and calculated average crystallite size was ∼25 nm which vary with dopant concentration. The EDX results of Zn 1−x Fe x O showed the 100% purity of Zn 1−x Fe x O samples. With the increase of Fe concentration, a slight decrease of energy bandgap (3.10 to 3.02 eV) was observed. FTIR spectra showed the presence of Zn-O and Fe-O bonds in the samples. The effect of Fe doping in ZnO also showed the variation in dielectric properties and ac conductivity of samples. Hysteresis curves were plotted which exhibit room temperature ferromagnetic (RTFM) behavior. 2 mol% Fe doped ZnO sample retained highest saturation magnetization of 11.2 emu g −1 . All samples exhibit above 90% degradation of methylene blue in just 90 min exposure to sunlight.