Studies On Preparation, Characterization And Photocatalytic Properties Of One-dimensional Nano Zinc Ferrites

Highly ordered Zinc Ferrite(ZnFe₂O₄) nanotube arrays are fabricated by using porous anodic aluminum oxide(AAO) template from sol-gel solution.Combined modern physical methods are used to characterize the structure,morphology and optical properties of the prepared samples,such as scanning electron microscopy(SEM),X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS),UV-Vis diffuse reflectance spectroscopy(UV-Vis DRS),and so on.The results indicate that the as-prepared ZnFe₂O₄ nanotubes with rough walls of 200 nm in diameter and 50 nm in wall thickness are orderly arranged in parallel.Their XRD patterns can be indexed to a pure cubic phase of ZnFe₂O₄.UV-Vis analysis shows that the absorption edges of nanotubes are around 550 nm,which indicates that these samples have possible activities under visible light.The photocatalytic activities of the as-prepared ZnFe₂O₄ nanotube arrays are investigated through the photoelectrodegradation of 4-chlorophenol(4-CP) solution under visible light irradiation.The factors influencing the degradation of 4-CP by the photocatalytic process such as initial concentration of 4-CP,pH,UV light intensity and air flow are examined.The stability of TiO₂ nanotubes is also evaluated.The results of the five repeated experiments under the same experimental conditions show that the photocatalytic degradation efficiency of 4-CP can be kept at above 50%.It is proved that the reaction follows the first-order reaction kinetics.The "timber-like" nanocrystalline ZnFe₂O₄ are prepared by a simple liquid reduction approach.The results of the SEM and TEM indicate that the as-prepared samples are aggregated by porous ZnFe₂O₄ rods.The photodegradation efficiencies of ZnFe₂O₄ powder and the "timber-like" nanocrystalline ZnFe₂O₄ is compared under visible light.The results indicate that the photocatalytic activities of the "timber-like" nanocrystalline ZnFe₂O₄ is superior to ZnFe₂O₄ powder.The photodegradation efficiency of the "timber-like" nanocrystalline ZnFe₂O₄ could reach 91.49%in 2 h,and the reaction follows the first-order eaction kinetics.