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.