Cyclic voltammetry (CV) was used to evaluate the electrocatalytic performance of Fe-N-C SANs for H2O2. The Fe-N-C SANs were loaded onto SPE at a density of 0.1 mg cm -2 . The CV curves of bare SPE and Fe-N-C SANs-coated SPE in the presence and absence of 2.5 mM H2O2 in 0.01 M phosphate-buffered saline (PBS, pH 7.4) are shown in Figure . The bare SPE exhibited a low current and weak response to H2O2, while Fe-N-C SANs-coated SPE showed a reduction peak at -0.1 V in PBS solution. Besides, the bare SPE showed a weak response at -0.64 V to 2.5 mM H2O2.