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

The present study, reports the synthesis of pure and Ni-doped (with varying concentration of nickel 1, 3, 6, and 9 wt%) alpha-Fe 2 O 3 (hematite) nanoparticles by chemical precipitation technique and investigate their structural, morphological, optical, magnetic and antimicrobial activities. The XRD pattern of pure and Ni-doped alpha-Fe 2 O 3 nanoparticles exhibit rhombohedral structure and the average size of alpha-Fe 2 O 3 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 alpha-Fe 2 O 3 . 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 alpha-Fe 2 O 3 samples were assessed using a vibrating sample magnetometer (VSM); the ensuing hysteresis loop of the Ni-doped alpha-Fe 2 O 3 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 mu g/ml of pure and Ni-doped alpha-Fe 2 O 3 NPs, the highest zone of inhibition was found against gram ( + ve) positive bacteria and was followed by the gram ( -ve) negative bacteria's.

Automated summary

The present study focuses on the synthesis and characterization of pure and Ni-doped alpha-Fe2O3 nanoparticles, as well as their structural, morphological, optical, magnetic, and antimicrobial properties. XRD analysis revealed the rhombohedral structure of the nanoparticles, with an average size of 39-47 nm. The addition of nickel resulted in a reduction in density dislocations, and UV-vis-DRS studies showed lower bandgap values for higher Ni-dopants. The nanoparticles displayed ferromagnetic behavior, as confirmed by VSM measurements. The antibacterial activity of the nanoparticles was assessed using the disc diffusion technique, which showed the highest inhibition zone against gram-positive bacteria at concentrations of 200 and 500 μg/ml.