Influence of Sm3+ ions on structural, optical and solar light driven photocatalytic activity of spinel MnFe2O4 nanoparticles

In this article, co-precipitation method was used to produce a series of samarium substituted manganese ferrite nanoparticles, MnFe2-xSmxO4 (x = 0.0, 0.5, 1.0, 1.5, 2.0) with oleic acid as surfactant. The effect of Sm3+ substitution and calcination temperature on the MnFe2O4 was explored. The MnFe2-xSmxO4 sample calcinated at 973 K induced an enhanced optical behaviour. The influence of Sm3+ ions on cationic distribution and optical properties of MnFe2O4 were probed by various physicochemical techniques. The presence of secondary orthorhombic (SmFeO3) phase with initial cubic phase was confirmed by doublet peak in the X-ray diffraction pattern. The particle size distribution of MnFe0.3Sm1.5O4 sample was about 40 nm from HRTEM. The visible light absorption ability extended as Sm content was increased up to x = 1.5 in MnFe2O4. At an optimum concentration of Sm as x = 1.5 in MnFe2O4, photocatalyst exhibited decrease in energy band gap (1.64 eV); as a result effective visible light driven photocatalytic activity was achieved than the pure MnFe2O4. The MnSm1.5Fe0.5O4 sample exhibits pronounced photodegradation towards Rose Bengal with in 50 min under direct sunlight illumination as energy input. The broad emission band is observed in the entire photoluminescence (PL) spectrum. Current study provides an excellent competency of rare earth substituted ferrite as a new class of photocatalyst and they found to be a beneficial in the field of environmental cleaning application.