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

Abstract

Electrochemical hydrogen peroxide (H 2 O 2 ) sensors are valuable tools in biological research and industrial applications for in situ monitoring H 2 O 2 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 H 2 O 2 . This platform showed an excellent response to H 2 O 2 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–N x sites, which resemble the peroxidase-type enzymes, contribute to the high activity of the Fe-N-C catalyst for the H 2 O 2 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 μ A μ M −1 cm −2 ) and a low detection reagent (40 μ l solution). Moreover, the as-prepared Fe–N–C/SPE was successfully applied to H 2 O 2 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 H 2 O 2 analytes, further improving its practical H 2 O 2 sensing applications.