Influence of Ni doping on hematite nanoparticles for enhanced structural, optical, magnetic properties and antibacterial analysis

Abstract

The present study, reports the synthesis of pure and Ni-doped (with varying concentration of nickel 1, 3, 6, and 9 wt%) α-Fe2O3 (hematite) nanoparticles by chemical precipitation technique and investigate their structural, morphological, optical, magnetic and antimicrobial activities. The XRD pattern of pure and Ni-doped α-Fe2O3 nanoparticles exhibit rhombohedral structure and the average size of α-Fe2O3 is determined to be 39 to 47 nm. With the addition of nickel, it is revealed that the estimated density dislocations linked to the agglomeration/cluster formations reduce as a result of the elimination of interstitial vacancies. According to UV–vis-DRS studies, the lowered bandgap values connected to the modest impact of structural changes were observed for larger Ni-dopants. The green emission bands at 522, 534, and 544 nm of the luminescence spectra show noticeable changes in peak strength, but there is no change in the emission bands. The fundamental stretching of Fe–O vibrations and the presence of Ni in prepared samples were identified in FTIR and Raman spectra. SEM micrographs show the spherical structure and the particle distributions of the Ni-doped α-Fe2O3. The SEM micrograph revealed that the observed particle size ranged from 39 to 57 nm, which is in good accord with XRD studies. Further, the magnetic characteristics of the pure and Ni-doped α-Fe2O3 samples were assessed using a vibrating sample magnetometer (VSM); the ensuing hysteresis loop of the Ni-doped α-Fe2O3 displays ferromagnetic behavior. In the present investigations, the disc diffusion technique has been used to examine the antibacterial activity. Thus, the results of antibacterial activities demonstrated that at concentrations of 200 and 500 µg/ml of pure and Ni-doped α-Fe2O3 NPs, the highest zone of inhibition was found against gram (+ve) positive bacteria and was followed by the gram (−ve) negative bacteria's.