Sol-gel auto-combustion developed Nd and Dy co-doped Mg nanoferrites for photocatalytic water treatment, electrocatalytic water splitting and biological applications

Sol-gel auto-combustion synthesis was considered for development of MgNd_0.5xDy_0.5xFe_2-xO₄ (x = 0.00, 0.01, 0.02, 0.03) nanoferrites to analyze the structural, optical, morphological, photocatalytic, magnetic, electrocatalytic, and antibacterial traits of nanomaterials. X-ray diffraction (XRD) patterns illustrate the existence of spinel phase for synthesised nano ferrites with no impurity phases. With increased neodymium (Nd) and dysprosium (Dy) content, the energy band gap of produced nanoferrites was decreasing from 1.73 to 1.49 eV. The magnetic characteristics indicates that with Nd and Dy doping, excellent saturation magnetization (M_s) and coercivity (H_c) in the range of 27.47–32.30 emu/g and 51.79–80.28 Oe were observed for produced nanoferrites. Electrocatalytic traits of developed nanoferrites were investigated for HER and OER in 0.5 N H₂SO₄ and 0.1 N KOH electrolyte using a calomel electrode as a reference electrode, respectively. According to photodegradation investigation, doped samples performed better in terms of photocatalytic efficiency under the specific conditions (catalytic dose = 0.05 g, dye concentration = 10 mg/L⁻ and pH = 7). The prepared MgNd_0.015Dy_0.015Fe_1.97O₄ (x = 0.03) nanoferrite sample shows higher photocatalytic activity due to increased active sites and smaller band gap. Furthermore, the catalyst efficiency did not decrease significantly after the five consecutive reuse cycles. The antibacterial effects of developed Mg spinel nanoferrites for gram-positive bacteria (Staphylococcus aureus) and gram-negative bacteria (Escherichia coli) are found to be effective. Therefore, with these superior electrocatalytic, photocatalytic, and antibacterial traits, the developed Mg nano ferrites are suitable for hydrogen evolution, wastewater treatment, and biological applications.