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

Abstract Zinc ferrite (ZnFe 2 O 4 ) nanoparticles and ZnFe 2 O 4 -TiO 2 nanocomposite have been synthesized by simple and effective co-precipitation method followed by annealing at 500 °C for 5 h. The x-ray diffraction patterns suggest ZnFe 2 O 4 and/or TiO 2 phases with no other impurities. TEM images demonstrate that ZnFe 2 O 4 nanoparticles are spherical in shape (9 ± 2 nm) and ZnFe 2 O 4 -TiO 2 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 ZnFe 2 O 4 nanoparticles (2.11 eV) and ZnFe 2 O 4 -TiO 2 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 ZnFe 2 O 4 and TiO 2 . The PL spectra with λ 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 ZnFe 2 O 4 -TiO 2 nanocomposite suggest its improved photocatalytic activity compared with ZnFe 2 O 4 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.