Exploring Influence of Zn 2+ Doping on Structural, Optical, Magnetic and Morphological Properties of Nickel Nano Ferrites, Synthesized via the Sol–Gel Route

ABSTRACT Single‐phase sofmagnetic Ni (1− x ) Zn x Fe 2 O 4 ferrite nanoparticles with x ranging from 0.0 to 1.0 in steps of 0.2 were prepared using the sol–gel auto‐combustion process. To investigate changes in structural parameters, XRD was used for the cubic spinel structure with significant orientation along the (311) plane and the Fd3m space group. The addition of Zn 2+ to the crystal structure modulates the lattice parameters and microstrain. FESEM micrographs exhibited porous features that varied with Zn 2+ concentration. EDS results confirm that the nanoparticles contain the expected elements, namely nickel, zinc, iron, and oxygen. FTIR results show an increase in band stretching at both octahedral and tetrahedral sites. The reduction in the optical band gap from 1.79 to 1.38 eV with increasing Zn 2 + content is attributed to cation redistribution between tetrahedral and octahedral sites, which alters the Fe 3d–O 2p electronic structure and enhances visible‐light absorption for photocatalytic applications. Beyond x = 0.4, magnetic dilution causes the magnetization to diminish, and overall coercivity reduces, suggesting superior soft magnetic behavior. The optimized sample( x = 0.4) shows superior photocatalytic degradation of methylene blue dye under visible light irradiation with 85.30% degradation efficiency and a rate constant of 0.02845 min − 1 . These results highlight a cost‐effective and reusable photocatalyst for environmental remediation.