Xiaozhen Ren

Facile synthesis of nanocrystalline Fe/Fe3C induced by bromide

Fe3C is a promising material with both high saturation magnetization and chemical stability. In this article, we present a facile sol–gel route for the synthesis of Fe3C/Fe nanocomposites, in which bromide was found to be the inducing agent for the conversion of FeCl3 to Fe3C. X-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer were used to characterize the composites. The experimental results show that the composition and magnetic properties of Fe3C/Fe composites can be controlled by changing reaction temperatures, reaction time and the amount of inducing agent. Moreover, the possible formation mechanism of as-prepared nanostructures is discussed.

Effect of Eu, Tb codoping on the luminescent properties of multifunctional nanocomposites

The synthesis (by a facile two-step co-precipitation process) and characterization, are reported for good dispersed core–shell structured Fe3O4@SiO2@Y2O3:Eu3+, Tb3+ nanocomposites with luminescent and magnetic properties. XRD patterns show that Fe3O4 core has crystallized with a good face-centered cubic structure; SiO2 layer is amorphous and Y2O3 layer is cubic. TEM images show the synthesis of core–shell structured composite microspheres of uniform size with rough surface. For nanocomposites with same host (Y2O3), upon excitation with UV irradiation, fluorescent spectra show that there is a strong emission at around 610 nm corresponding to the forced electric dipole 5D0–7F2 transition of Eu3+ and at around 545 nm corresponding to 5D4–7F5 transition of Tb3+. We speculate that there exists energy transfer from Tb3+ to Eu3+ ions from excitation spectra. Therefore, the multifunctional nanocomposites are expected to develop many potential applications in biomedical fields.