Mixed Mg–Co spinel ferrites: Structure, morphology, magnetic and photocatalytic properties

CoxMg1-xFe2O4 (where x was 0.0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1) spinel ferrites were synthesized by the sol-gel combustion method using citric acid as fuel, following rules of propellant chemistry. Amorphous powders then calcined at 700 °C for 3 h. Structural analysis X-Ray diffraction (XRD), FTIR Raman spectroscopy confirmed formation a cubic structure where cation distribution inversion degree depended on Co2+ Mg2+ ion content. Accordingly, lattice parameter varied between 8.3703 Å (MgFe2O4) 8.3919 (Co0.9Mg0.1Fe2O4) did crystallite size, from 34 nm (Co0.1Mg0.9Fe2O4) to 48 (Co0.9Mg0.1Fe2O4). Scanning electron microscopy (SEM) showed multigrain agglomerates. Determined values maximal remanent magnetization, well coercive field, content increased with substitution diamagnetic ions magnetic ions. Most impressive is increase field 74 Oe MgFe2O4 1000 CoFe2O4, an magnetization in 10 kOe 27.4 emu g?1 75.7 g?1. The determined optical band gaps UV/Vis DRS measurements strong dependence content, morphology, decreasing 2.09 eV 1.42 CoFe2O4. photocatalytic efficiency as-synthesized investigated monitoring degradation Methylene Blue (MB) under natural sunlight, artificial light source emitting visible light. Different conditions MB such photocatalyst loading, molar concentration MB, pH investigated. Results have shown that both excessive amounts cobalt retarded process. Co0.9Mg0.1Fe2O4 considerable activity (74.5% after 4 h) unexpected but possibly connected structural anomalies. best sunlight achieved (82% h), while Co0.1Mg0.9Fe2O4 (79% h).