Development of ferrimagnetic (Mn0.6Cr0.6Co0.6Fe0.6Al0.6)O4 high entropy oxide for photo-Fenton degradation of organic dye

Herein, we report the development of nanosized MHEO composed of Mn, Cr, Co, Fe, and Al, (Mn0.6 Cr0.6 Co0.6 Fe0.6 Al0.6)O4 through sol-gel method, followed by calcination at high temperature. X-ray diffraction pattern (XRD) and transmission electron microscopy (TEM) analyses confirmed the successful formation of single-phase nanosized HEO, while X-ray photoelectron spectroscopy (XPS) analysis revealed the oxidation states of the individual elements present in it. This inverse spinel-structured oxide exhibited soft ferrimagnetic behavior, despite the fact that the individual oxides are either ferrimagnetic, paramagnetic or antiferromagnetic at room temperature. It exhibited excellent photo-Fenton catalytic degradation of organic dye, methylene blue (MB) and its complete degradation was achieved in 90 min. The successful degradation and mineralization of MB through photo-Fenton process were evident from mass spectroscopic analysis. The observed high MB degradation activity can be attributed to the generation of electron-hole pair under UV light as well as to the contribution of all constituent metal ions except Al3+ in providing additional active redox sites for Fenton degradation. The magnetic property of the developed MHEO provided an added advantage, making it easier to recover after recycling studies.