A hybrid composite of recycled popcorn-shaped MnO2 microsphere and Ox-MWCNTs as a sensitive non-enzymatic amperometric H2O2 sensor

Abstract

Taking full advantage of the manganese (Mn) species which were produced in the fabrication of graphene oxide (GO) using modified Hummers method, loosely popcorn-shaped MnO2 microspheres were synthesized accordingly. A network composite of oxidized multi-walled carbon nanotubes (Ox-MWCNTs) and MnO2 (MnO2-Ox-MWCNTs) was assembled by a facile ultrasound-assisted approach. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) confirmed the successful preparation of MnO2 and the assembly of MnO2-Ox-MWCNTs. Based on drop-casting route, MnO2-Ox-MWCNTs composite modified glassy carbon electrode (GCE) (MnO2-Ox-MWCNTs/GCE) was constructed. The electrochemical performances of the proposed electrode were investigated by cyclic voltammetry (CV) and amperometric method. Due to the synergistic effect between loosely popcorn-shaped MnO2 microspheres and Ox-MWCNTs, the proposed electrode showed high peroxidase-like electrocatalysis activity for H2O2 detection. The peak currents linearly increased with H2O2 concentrations in the range 0.80–1000 μM, and limit of detection (LOD) was 0.38 μM. The proposed electrode could be employed for qualitative detection and quantitative determination of H2O2 in milk samples.