Aegle Marmelos Mediated Green Synthesis of Chromium-doped Nickel Ferrite Nanoparticles for Antibacterial Activity

Abstract

Here, we present the preparation of (NiFe_2−xCr_xO₄), with x = 0.0, 0.1, 0.2, 0.3 and 0.4 nanoparticles using a green synthesis method, employing the extract of Aegle marmelos (Bel leaves) as biogenic green fuel. The single-phase production having an FCC-type simple cubic spinel structure was verified by XRD analysis. The prepared nanoparticles exhibit crystallite sizes of 14 to 8 nm. The lattice constant (a) calculated from XRD data decreased from 8.346 Å to 8.307 Å. The formation of spherical grains with some agglomeration was observed through FE-SEM analysis. The surface area determined by BET analysis increases with Cr³⁺ content and ranges from 33.62 m²/g to 59.32 m²/g. The band gap energy calculated using the Tauc plot was in the range 1.57 eV-1.74 eV. Saturation magnetization decreases with Cr³⁺ content. The low coercivity values suggest the superparamagnetic nature of the prepared nanoparticles. No systematic dependence of antibacterial properties of the synthesized nanoparticles was found against Gram-positive (S. Aureus and B. Subtilis) and Gram-negative (E. coli, K. Pneumonia) bacteria for varying Cr³⁺ content. However, the sample with x = 0.2 exhibits enhanced antibacterial activity compared to the other compositions.