Interface Co‐Assembly Synthesis of Magnetic Fe3O4@mesoporous Carbon for Efficient Electrochemical Detection of Hg(II) and Pb(II)

Abstract In recent years, efficient and porous carbon‐layer‐modified magnetic metal oxides demonstrate potentials for the significant improvement of catalytic and adsorption performance. In this study, a novel magnetic coreshell Fe 3 O 4 @mesoporous carbon (Fe 3 O 4 @MPC) nanochain electrochemical sensor is constructed by using resorcinol‐formaldehyde resin and magnetic Fe 3 O 4 nanospheres as the carbon shell precursor and core, respectively, with a simple emulsion self‐assembly strategy. Microstructural characterizations revealed that the carbon shell exhibited a mesopore distribution of ≈40 nm and the diameter of Fe 3 O 4 nanospheres embedded into carbon is ≈280 nm. The introduction of mesoporous carbon layer increased the electrical conductivity of the active material and maintained the adsorption properties of magnetic Fe 3 O 4 . The synergistic effect of the mesoporous carbon layer and Fe 3 O 4 nanochain is beneficial to electrochemically detect heavy metal ions (HMIs). Under optimal conditions, the typical Fe 3 O 4 @MPC‐2/GCE exhibited excellent electrochemical sensing for detecting Hg(II) and Pb(II), with limits of detection (LOD) of 7.8 n m and 12.1 n m (S/N = 3), respectively. These good results are attributed to the Fe 3 O 4 @MPC nanochain structure and a relatively high specific surface area. This study provides a novel method to prepare magnetic mesoporous carbon nanochain composites for constructing sensitive electrochemical sensors to monitor water quality.