Hierarchical SrTiO3/NiFe2O4 composite nanostructures with excellent light response and magnetic performance synthesized toward enhanced photocatalytic activity

Abstract

Being capable of gathering advanced optical, electrical and magnetic properties originating from different components, multifunctional composite nanomaterials have been of concern increasingly. Herein, we have successfully demonstrated the preparation of SrTiO₃/NiFe₂O₄ porous nanotubes (PNTs) and SrTiO₃/NiFe₂O₄ particle-in-tubes (PITs) via a single-spinneret electrospinning and a side-by-side-spinneret electrospinning, respectively. The products were characterized by using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, UV-visible diffuse reflectance spectra and a vibrating sample magnetometer in detail. The results indicate that SrTiO₃/NiFe₂O₄ PNTs are the heterojunction nanotubes by connecting perovskite SrTiO₃ and spinel NiFe₂O₄ nanoparticles, but SrTiO₃/NiFe₂O₄ PITs are the self-assembled core/shell structures by embedding SrTiO₃ nanoparticles into NiFe₂O₄ nanotubes. Compared with pure SrTiO₃ nanofibers, the two SrTiO₃/NiFe₂O₄ composites exhibit a powerful light response and excellent room temperature ferromagnetism. The magnetic separations directly reveal that such amazing recycling efficiencies of about 95% for SrTiO₃/NiFe₂O₄ PNTs and about 99.5% for SrTiO₃/NiFe₂O₄ PITs are obtained. Furthermore, both the magnetic composites perform considerable photocatalytic activity in the degradation of rhodamine B. We propose that Kirkendall-diffusion and phase-separation are probably responsible for the formation of SrTiO₃/NiFe₂O₄ PITs, and this work could provide a feasible way to assemble the core/shell structures of different materials.