Facile single phase synthesis of Sr, Co co-doped BiFeO3 nanoparticles for boosting photocatalytic and magnetic properties

In this article, we demonstrate the synthesis of single phase Bi1-xSrxFe1-yCoyO3 (x = y = 0, x = 0.02; y = 0.01, 0.03, 0.05, 0.07) using a facile sol-gel route. The powder X-ray diffraction measurements of all the samples confirm the pure phase rhombohedral structure with a small lattice distortion. The morphological analysis demonstrated decrease in average particle size from similar to 64 to 41 nm with increasing Co doping in Bi0.98Sr0.02Fe1-yCoyO3 due to slower growth rate. Mossbauer study reveals the change in oxidation state of iron (Fe3+ -> Fe2+) at higher doping concentration of Co. Further, the successful co-doping of Sr, Co into BiFeO3 lattice remarkably enhances the saturation magnetization value from 0.8 emu/g to 2.3 emu/g and remnant magnetization from 0.08 emu/g to 0.532 emu/g. The enhanced magnetic properties of Sr, Co co-doped BiFeO3 nanoparticles is ascribed to the breaking of cycloidal spin structure, more number of uncompensated spin on the surface, and oxygen vacancies. Moreover, these samples were found to be highly efficient for the degradation of Rhodamin B (RhB) dye under visible light irradiation. The best RhB degradation activity was observed with 7% Co doping Bi0.98Sr0.02Fe1-yCoyO3 (BSFCO7) due to its lower bandgap, reduced average particle size and larger specific surface area.