Carbon-Doping Mesoporous β-Mo₂C Aggregates for Nanomolar Electrochemical Detection of Hydrogen Peroxide

The development of a nonenzymatic electrochemical sensor with nanomolar detection of H2O2 has been highly desirable due to its wide applications in bioanalysis. In this paper, the glassy carbon electrode (GCE) modified by carbon-doping molybdenum carbide (β-Mo2C/C/GCE) was simply fabricated by simple drop-coating method and used to detect H2O2 in pretreated human serum. The β-Mo2C/C hierarchical structure is obtained by a one-step pyrolysis of the single-crystal [(H2L)2(Mo8O26)]n [L = N,N′-bis(3-pyridin)-1,4-xylyenediamine] and constructed from amounts of nanoparticles (∼10 nm) with a mesoporous size distribution of 42.46 nm. At room temperature, the β-Mo2C/C/GCE sensor has a high sensitivity of 247.73 μA mM–1 cm–2, a low detection limit of 90 nM (signal/noise = 3), as well as a wide linear range of 0.27 μM–2.39 mM, and it shows better electrocatalytic performance of H2O2 than the molybdenum oxide (obtained from the same precursor) modified glassy carbon electrode (α-MoO3/GCE). Such outstanding electrocatalytic performances are related to the synergistic effect of the inherent characteristics of the β-Mo2C/C material. The satisfactory test results of the human serum samples indicate that the β-Mo2C/C/GCE sensor can be used as a good candidate for real-time detection of H2O2 in biological, food, and environmental fields.