MnO2/multi-walled carbon nanotubes based nanocomposite with enhanced electrocatalytic activity for sensitive amperometric glucose biosensing

Functional nanostructured transition metal oxides hold great promise in catalysis based sensors due to their superb catalytic activity, good stability, ease of preparation and cost-effectiveness. In this work, MnO2 nanowires and MnO2/multi-walled carbon nanotubes (MWCNTs) nanocomposite were prepared via a simple hydrothermal method. The MnO2/MWCNTs nanocomposite was developed by deposition of MnO2 on MWCNTs surface, which have abundant hydrophilic groups facilitating ion-adsorption and nucleation process. The MWCNTs/MnO2 exhibited higher catalytic activity upon hydrogen peroxide (H2O2) electrooxidation, with reduced overpotential by 100 mV and 220 mV in contrast to those values of MWCNTs and MnO2 nanowires, respectively. Thus the MnO2/MWCNTs nanocomposite modified glass carbon electrode (GCE) enabled to detect H2O2 sensitively. Moreover, by incorporation of glucose oxidase (GOx), a glucose biosensor GOx/MnO2/MWCNTs/GCE was prepared. The as-proposed biosensor had wide linear range (5–200 μM and 0.2–1 mM) and a low detection limit of 2 μM (S/N = 3), which could be applicable to detect real sample with satisfying accuracy and reproducibility. Due to the superb electrochemical properties, the as-developed MnO2/MWCNTs nanocomposite is prospected in electrochemical sensor, electrocatalysis and supercapacitor.