Eco-Friendly Synthesis of Ag-Doped MgFe₂O₄ Nanoferrites with Enhanced Photocatalytic Properties

In the present work, pure and Ag-doped magnesium ferrite (MgFe₂O₄) nanoparticles were synthesized and studied for their structural, optical, surface, morphological, and photocatalytic properties. X-ray diffraction analysis confirmed the formation of cubic spinel ferrite structure with a prominent (311) reflection peak. The crystallite size decreased from 31.8 nm to 17.6 nm with increasing Ag concentration, indicating that Ag doping suppresses crystal growth. The lattice parameter remained nearly constant in the range of 8.38–8.39 Å, while slight variations in microstrain suggested lattice distortion due to dopant incorporation. SEM observations confirmed spherical nano-sized particles with increased agglomeration at higher Ag concentration. BET surface area analysis revealed improved textural properties after doping. The specific surface area increased from 30.2 m²/g for the pure sample to 40.3 m²/g for the doped sample, accompanied by enhanced pore volume, confirming the mesoporous nature of the nanoparticles. UV–Visible spectroscopy showed strong absorption in the visible region with band gap energies varying from ~2.1 to 2.06 eV. The reduction in band gap energy after doping indicates enhanced visible-light absorption capability. Photocatalytic studies using Congo Red dye under visible-light irradiation demonstrated significant enhancement in degradation efficiency after Ag doping. Among all samples, 6% doping of Ag showed the highest photocatalytic degradation efficiency of 99.7% within 150 minutes. The enhanced performance is mainly attributed to reduced crystallite size, higher surface area, improved porosity, and better visible-light response. These results suggest that Ag-doped MgFe₂O₄ nanoparticles are promising materials for environmental remediation and wastewater treatment applications.