Synergetic enhancement of electrochemical H2O2 detection in a nitrogen-doped carbon encapsulated FeCo alloy architecture

Abstract

The development of Earth-abundant metal-based non-enzymatic electrodes with ultralow metal loadings for the efficient detection of hydrogen peroxide (H₂O₂) is highly desirable. We report here a remarkable three-dimensional nitrogen-doped porous carbon (NPC) encapsulated Earth-abundant metal architecture, i.e., NPC encapsulating FeCo alloy nanoparticles toward highly efficient electrochemical H₂O₂ detection. Specifically, an Fe_0.06Co_0.04@NPC-950 modified electrode can show excellent electrochemical performance for non-enzymatic H₂O₂ sensing in neutral media, with a wide linear range of 0.004 to 8 mM, a high sensitivity of 794 μA mA⁻¹ cm⁻² and a low limit of detection (LOD) of 0.13 μM, outperforming most of the reported non-noble metal electrocatalysts. Meanwhile, the fabricated Fe_0.06Co_0.04@NPC-950 modified electrode is capable of real-time monitoring of H₂O₂ in commercial orange juice, milk and serum, revealing its application potential toward the accurate detection of H₂O₂ in real-sample analysis. This electrode also has high selectivity, long-term stability and good reproducibility. Its excellent performance is correlated with the synergetic catalysis of the FeCo alloy, nitrogen-rich NPC with a large specific surface area (SSA) and the core–shell structure protecting the active sites from corrosion. This study offers an efficient pathway for developing high-performance and Earth-abundant catalysts toward electrochemical H₂O₂ detection.