Novel sensitive amperometric hydrogen peroxide sensor using layered hierarchical porous α-MoO3 and GO modified glass carbon electrode

Abstract

The nonenzymatic electrochemical H2O2 sensor based on molybdenum oxides has been rarely reported. In this work, a nonenzymatic electrode, hierarchical porous α-MoO3 and graphene oxide decorated glass carbon electrode (α-MoO3/GO/GCE) used for H2O2 electrochemical detection, is firstly fabricated by simple layer-by-layer assemble method, in which the α-MoO3 is derived by one-step pyrolysis of the regular organic-inorganic hybrid [(H2L)2(Mo8O26)]n [HL = N-(pyridin-3-ylmethyl)pyridine- 3-amine] single crystal precursor. The wedge-shaped morphology of the material is accumulated by micro-slices which comprise of nanosheets and small particles with average size of 25 nm. Meanwhile, different types of meso- and macro-pores with the size distributions of 4–6, 20–35 and 100–150 nm are observed, respectively. The α-MoO3/GO/GCE sensor based on the optimal ratio of 1:1 shows excellent electrocatalytic H2O2 property at room temperature. It displays the broad linear detection from 0.92 μM to 2.46 mM and the high sensitivity is calculated to be 391.39 μA mM−1 cm−2 with a low detection limit of 0.31 μM (S/N = 3). The sensor can achieve 95% steady state current within 5 s and present well stability, reproducibility and anti-interference during H2O2 detection. Furthermore, the sensor is applied for the determination of H2O2 in human serum samples. The excellent performances of this sensor are related to the hierarchical porous structure of α-MoO3 and its synergistic effect with GO.