Eco-friendly synthesis of Mg0.5Ni0.5AlxFe2-xO4 magnetic nanoparticles and study of their photocatalytic activity for degradation of direct blue 129 dye

In this research, Mg0.5Ni0.5AlxFe2-xO4 (x = 0.5, 1, 1.5) spinel ferrites were synthesized by facile sol-gel technique. The effects of the aluminum ion as a dopant on structural, morphological, optical, magnetic properties, and photocatalytic activity of spinel ferrites have been investigated using various analytical techniques. The XRD results approve the formation of a single-phase cubic spinel structure. It is also observed that the crystallite size decreases as Al3+ concentration increases. The FESEM and TEM analyses indicate a nanosized particle morphology. According to the VSM results, the saturation magnetization (M-s) decreases by the increase of Al content. Optical band gap energy studies of samples express that E-g value increases from 2.55 to 2.67 eV by increasing Al3+ dopant, which is confirmed by UV-vis DRS. The photocatalytic activity of the catalysts was evaluated for the degradation of DB129 as a model reaction under visible light irradiation. Based on our results, there is a direct correlation between photocatalytic activity and the amount of Al. Hence, the catalyst with x = 1.5 illustrates better degradation than the catalyst with x = 1 and 0.5. The catalyst with x = 1.5 is also capable to degrade the direct blue 129 up to 94%.