Synergistic effects of Fe-Se dual single-atom sites for boosting electrochemical nonenzymatic H2O2 sensing

The study of single atoms in the field of electrochemical sensing is at the early stage. How to boost the catalytic performance of single atoms is still a big challenge. Herein, we prepare Fe-Se dual single-atom sites on N-doped ultrathin carbon carrier (Fe 1 Se 1 /NC) for realizing highly sensitive nonenzymatic detection of H 2 O 2 . Fe 1 Se 1 /NC was synthesized through the pyrolysis strategy, and then was characterized by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) mapping, high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS), and electrochemical techniques, respectively. The results displayed that Fe and Se both existed in an atomically dispersed status. Compared to the single-atom Se or Fe catalyst (Se 1 /NC or Fe 1 /NC), the Fe 1 Se 1 /NC significantly boosted the electrocatalytic activity for H 2 O 2 reduction. The Fe 1 Se 1 /NC modified electrode could be used to detect H 2 O 2 in a wide linear range of 0.02 mM to 13 mM with a high sensitivity of 1508.6 µA·mM −1 ·cm −2 and a low detection limit of 11.5 µM. Moreover, the sensor was successfully employed for detecting H 2 O 2 in disinfectant and urine samples. This work provides a novel design of dual-atom catalysts for excellent electrochemical sensing applications.