Magnetically separable copper substituted cobalt–zinc nano-ferrite photocatalyst with enhanced photocatalytic activity

A series of nano crystalline copper substituted cobalt zinc ferrites, Co0.6Zn0.4CuxFe2−xO4 (x=0.2, 0.4, 0.6, 0.8 and 1.0) with cubic spinel crystal structure were synthesized by sol–gel auto combustion method. The X-ray diffraction analysis confirmed the formation of cubic phase with Fd-3m space group of all the prepared nano-ferrites. The lattice parameter was found to increase with increase in copper substitution. This may be attributed to larger ionic radius of copper as compared to that of iron. The electrical studies revealed that all prepared ferrites are semiconducting in nature. The saturation magnetization was found to be maximum at x=0.4, obeying Neel׳s two sub-lattice model and decreased thereafter due to spin canting effect. The photo catalytic degradation of methyl orange (MO) dye by Co0.6Zn0.4CuxFe2−xO4 (x=0.2, 0.4, 0.6, 0.8 and 1.0) ferrite was studied under visible irradiation. Significant enhancement in photo degradation of MO can be ascribed to the B-site occupancy of copper ion. This catalyst is also well separable from water media by applying external magnetic field, thus it can act as a promising catalyst for the remediation of textile wastewater.