Novel Fe@Fe-O@Ag nanocomposite for efficient non-enzymatic sensing of hydrogen peroxide

Here, we present a novel non-enzymatic electrochemical sensor based on a zerovalent iron–iron oxide–silver nanocomposite (Fe@Fe-O@Ag) which is suitable for highly sensitive detection of hydrogen peroxide. Silver nanoparticles were prepared by simple reduction of silver ions on the surface of nanoscale zerovalent iron (nZVI) owing to the strong reductant efficiency of nZVI. The morphology, chemical and phase composition of the Fe@Fe-O@Ag nanocomposite was monitored by TEM, SEM, X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX). The electrochemical properties of Fe@Fe-O@Ag modified glassy carbon electrodes were characterized by voltammetric techniques and electrochemical impedance spectroscopy (EIS). The experimental data indicated that Fe@Fe-O did not contribute significantly to hydrogen peroxide sensing. Thus, Fe@Fe-O just serves as a substrate for the deposition of silver nanoparticles, whereas H2O2 detection is principally effected by the silver nanoparticles. Electrodes modified with the Fe@Fe-O@Ag nanocomposite showed a stable and sensitive response towards hydrogen peroxide reduction, exhibiting a wide linear dependence over H2O2 concentrations from 5 μmol L−1 to 1 mmol L−1 with a sensitivity of 460.34 μA μM−1 cm−2 and detection limit of 5.19 × 10−9 mol L−1. These results imply that the proposed Fe@Fe-O@Ag nanocomposite could be successfully used as a highly efficient and stable platform for hydrogen peroxide detection.