Fabrication of ternary CNT/PPy/KxMnO2 composite nanowires for electrocatalytic applications

CNT/PPy/KxMnO2, a novel ternary core–shell nanowires, was successfully prepared by a two-step self-assembly method and utilized as an electrocatalyst for the oxidation of hydrogen peroxide. The as-synthesized products were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy and Fourier-transform infrared spectra (FTIR) measurements. The results exhibited that the KxMnO2 nanosheets were grown on the surface of CNT/PPy core–shell nanotubes. The planes of the KxMnO2 nanosheets were more or less perpendicular to the CNT/PPy nanotubes. Cyclic voltammetry (CV) results demonstrated that the CNT/PPy/KxMnO2 composite nanowires, as a nonenzyme catalyst, performed well with regards to the oxidation of hydrogen peroxide in 0.1 M phosphate buffer solution (pH 7.0). The composite had a fast response with a linear range of 5.0 μM to 9.7 mM and a relatively low detection limit of 2.4 μM (S/N = 3). The sensitivity of the sensor for H2O2 was 114.6 μA mM−1 cm−2. These excellent properties might be due to the large surface area of the composite nanowires and the quick electron transfer promoted by the combination of CNT and PPy.