Studies on structural and optical properties of nano ZnFe2O4 and ZnFe2O4 TiO2 composite synthesized by co-precipitation route

Zinc ferrite (ZnFe2O4) nanoparticles and ZnFe2O4-TiO2 nanocomposite have been synthesized by simple and effective co-precipitation method followed by annealing at 500 degrees C for 5 h. The x-ray diffraction patterns suggest ZnFe2O4 and/or TiO2 phases with no other impurities. TEM images demonstrate that ZnFe 2 0 4 nanoparticles are spherical in shape (9 +/- 2 nm) and ZnFe2O4-TiO2 nanocomposite exhibits spherical-like morphology (11 +/- 3 nm). HRTEM and SAED studies further confirm the phase purity of the samples and reveal the formation of core-shell in case of the composite. The direct band gap of ZnFe2O4 nanoparticles (2.11 eV) and ZnFe2O4-TiO2 nanocomposite (2.30 eV) demonstrate their ability as visible light photocatalysts. The larger band gap of the composite may be due to the mixing effect of bandgap and the interfacial coupling effect between ZnFe2O4 and TiO2. The PL spectra with lambda(ex) = 317 nm display peaks corresponding to the recombination of charge carriers in deep traps of surface localized states and lattice defects. The nature of PLE peaks for the ZnFe2O4-TiO2 nanocomposite suggest its improved photocatalytic activity compared with ZnFe2O4 nanoparticles. Such results provide new prospects for optimizing and improving the properties and performance of semiconductor nanocomposites in photocatalytic degradation of dyes and water splitting.