Highly Efficient Sensing of Hydrogen Peroxide Based on Atomically Dispersed Iron- and Nitrogen-Doped Carbon

Abstract

Electrochemical hydrogen peroxide (H2O2) sensors are valuable tools in biological research and industrial applications for in situ monitoring H2O2 levels with the advantages of simplicity, portability, rapid response, and low cost. Herein, we demonstrate a novel electrochemical sensing platform based on Fe- and N-doped C composite (Fe–N–C) modified electrodes for sensitive detection of H2O2. This platform showed an excellent response to H2O2 reduction in near-neutral pH solutions with a low reduction potential and high sensitivities. The results of site-poisoning experiments suggest that the atomically dispersed Fe–Nx sites, which resemble the peroxidase-type enzymes, contribute to the high activity of the Fe-N-C catalyst for the H2O2 reduction reaction. Further, we developed a screen-printed electrode (SPE) modified with Fe–N–C with excellent electrocatalytic performances, including a favorable sensitivity (24.95 ± 0.77 μA μM−1 cm−2) and a low detection reagent (40 μl solution). Moreover, the as-prepared Fe–N–C/SPE was successfully applied to H2O2 sensing in an actual milk sample, with good recovery (between 98% and 102%). The as-prepared Fe–N–C/SPE sensor also exhibits superior selectivity, stability, and reproducibility, making it a promising candidate as a portable platform for H2O2 analytes, further improving its practical H2O2 sensing applications.