LAUSR

Abstract The present work reports the synthesis of ZnFe2O4 and ZnO-Zn1-xMxFe2O4+δ (Ln = Sm, Eu and Ho) nanomaterials by conventional solid state reactions between Ln2O3, Zn(NO3)2, Fe(NO3)3·9H2O and/or FeCl3·6H2O raw materials at 800 °C for 10 h and 15 h. Stoichiometric and nonstoichiometric reactions were explored for the synthesis of ZnFe2O4. The two Fe sources (Fe(NO3)3 and FeCl3) were used to study the proper raw material type for the synthesis of the ZnFe2O4. The synthesized nanomaterials were characterized by powder X-ray diffraction (PXRD) technique. Rietveld analysis showed that the obtained materials were crystallized well in cubic crystal system with the space group Fd3m and lattice parameters a = b = c = 8.4 A. The rietveld data showed that the purity of ZnFe2O4 was increased from 14% to 88% when the Fe source was changed from FeCl3 to Fe(NO3)3 meanwhile the reaction time was changed from 10 to 15 h. However, the purity was increased to 96% when the stoichiometry of Zn:Fe was changed from 1:2 to 0.8:2 at 800 °C for 15 h. The PXRD data revealed that dopant ion type had a considerable influence on the crystal phase purity of the obtained materials. It was found that Yb2O3 decreased more the purity of the obtained target compared to the other dopant ions. Ultraviolet-visible spectra showed that the synthesized nanomaterials had strong light absorption in the visible light region. Photocatalytic performance of the as-synthesized ZnFe2O4 was investigated for the degradation of pollutant Malachite Green (MG) in aqueous solution under direct visible light irradiation. The degradation yield at the optimized condition (0.09 mL H2O2, 30 mg catalyst and 60 min) was 98%.