Facile Synthesis of Carbon-Encapsulated Fe3O4 core/shell Nanospheres for Application in Pb(II) Electrochemical Determination

In this study, carbon-encapsulated Fe3O4 core/shell nanospheres (Fe3O4@C) were synthesized by a facile method and characterized by transmission electron microscopy, scan electron microscopy, X-ray diffraction, IR spectroscopy and Raman spectroscopy. Furthermore, Fe3O4@C nanospheres electrode was characterized by cyclic voltammetry and electrochemical impedance spectra. The Fe3O4@C nanospheres electrode exhibited remarkable electrocatalytic activity towards Pb(II) oxidation with higher limit of detection and sensitivity of 0.17 mu M and 95.6 mu A/mu M compared to other active materials on electrochemical detection of Pb(II) reported in previous works. Moreover, the Fe3O4@C nanospheres electrode exhibited high cycling stability and long-term durability. These results were attributed to the porous structure of the Fe3O4@C nanospheres electrode, which enabled the Fe3O4@C nanospheres to become highly accessible to the metal ion and provided more void volume for the reaction with metal ions. This work suggests that there is great potential in employing the Fe3O4@C nanospheres as heavy metal ions sensors.