N, O-Codoped Honeycomb-Carbon Supported Ni3S2 Fabricated by Melamine Pyrolysis Gas-Bath Method for Electrochemical Sensing Towards Pb2+ With High Sensitivity

Abstract

Various pyrolysis atmosphere types have a significant effect on the chemical compositions and carbon structures of the carbon-based nano-materials. Melamine is easy to be pyrolyzed to form gases containing C and N sources. In this study, N, O-codoped honeycomb-carbon supported Ni₃S₂ nanocomposites (CN@Ni₃S₂) have been fabricated with melamine pyrolysis product gas as the atmosphere source. The gas from in situ pyrolysis of melamine was used for the first time as a gas bath to study the doping of non-metallic elements in inorganic materials. The structure and morphology of the as-prepared nanocomposites were characterized by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy (Raman), scanning electron microscopy (SEM), transmission electron microscopy (TEM), specific surface area measurement (BET), and x-ray photoelectron spectroscopy (XPS). The as-synthesized composite modified glassy carbon electrode (GCE) has high sensitivity and a low detection limit for electrochemical sensing of Pb²⁺ ions, in which the current signal of the CN@Ni₃S₂/GCE modified electrode was linear with the concentration of Pb²⁺ in the range from 0.35 nM to 11.5 μM with a detection limit of 0.83 nM. At the same time, the sensor has high selectivity, long-term stability, repeatability, and reproducibility and anti-interference ability to meet actual sample detection. This study could provide a new strategy for the structural regulation of composite electrode modified materials and sensitive sensing detection of heavy metal ions.