Fe3C-functionalized 3D nitrogen-doped carbon structures for electrochemical detection of hydrogen peroxide

Fe3C-functionalized three-dimensional (3D) porous nitrogen-doped graphite carbon composites (Fe3C/NG) were synthesized via a facile solution-based impregnation and pyrolysis strategy using the commercially available melamine foam and FeCl3 as precursors. The structural characterizations confirmed that Fe3C nanoparticles with an average core size about 122 nm were assembled on the surface of the carbonized melamine foam (CMF) skeletons. The electrochemical measurements demonstrated the superior electrocatalytic activity of the advanced Fe3C/NG composite for hydrogen peroxide reduction reaction in 0.1 mol/L PBS electrolyte and the limit of detection of H2O2 is estimated to be 0.035 mmol/L at a signal-to-noise ratio of 3 with a wide linear detection range from 50 μmol/L to 15 mmol/L (R2 = 0.999). Compared with the pure CMF, the Fe3C/NG exhibited higher catalytic activity, more stable response, lower detection limit, higher selectivity and a wider detection range, which could be attributed to the synergic effect between the two types of active sites from the iron carbide species and the nitrogen-doped graphite carbon. Meanwhile, the large surface area, high conductivity and the improved mass transport from the 3D porous material can also promote the electrochemical sensing performance. Moreover, the Fe3C/NG-based electrochemical sensor showed high anti-interference ability and stability for H2O2 detection. Thus, the novel and low-cost Fe3C/NG composite may be a promising alternative to noble metals and offer potential applications in various types of electrochemical sensors, bioelectronic devices and catalysts.