Molybdenum nitride/nitrogen-doped multi-walled carbon nanotubes hybrid nanocomposites as novel electrochemical sensor for detection l-cysteine

• Establish a novel, facile and effective synthetic method of MoN/N-MWNTs.
• MoN/N-MWNTs exhibiting high conductivity and surface area due to N-MWNTs.
• Improved electrocatalytic activity towards l-CySH at MoN/N-MWNTs/GCE.
• Obtained the optimal loading amount of MoN for l-CySH sensor.
• A wide measurement range and a rapidly response.

In this work, we reported a novel, facile and effective strategy by using hydrothermal reaction and following high-temperature pyrolysis under the ammonia flow to fabricate the molybdenum nitride nanosheets/N-doped multi-walled carbon nanotubes (MoN/N-MWNTs) hybrid nanocomposite. MoN/N-MWNTs nanocomposite was characterized via X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and electrochemical methods. This nanocomposite exhibits excellent electrocatalytic oxidation of l-cysteine (l-CySH). An amperometric l-CySH sensor was constructed based on the MoN/N-MWNTs modified glassy carbon electrode. The as-prepared MoN/N-MWNTs nanocomposite has favourable conductivity, large surface area due to the MWNTs as supporter and highly exposed active sites of MoN. Moreover, the influence of different loading amounts of MoN was researched. The optimized MoN/N-MWNTs catalyst showed a wide detection range that was composed by two line segments (5 μM– 0.79 mM and 0.79 mM–12.60 mM), a sensitivity of 198.59 nA μM−1 cm−2 in the low concentration range, a rapidly response within 1.5 s as well as good reproducibility and stability.

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