In the present work, we report a one-step pyrolysis synthesis of molybdenum nitride nanorods (MoN NRs) using ammonium heptamolybdate tetrahydrate as a precursor. Properties of MoN NRs have been improved by the sulfur-doped graphitic carbon nitride (MoN@S-GCN) nanocomposite, which has been used to modify the glassy carbon electrode (GCE) for the electrochemical determination of chloramphenicol (CAP). The large surface area of S-GCN-anchored MoN NRs in the nanocomposite demonstrates a synergistic effect of the transport of a kinetic barrier electron and a well-defined redox cycle within the ferricyanide system. In the electrochemical determination of CAP over MoN@S-GCN/GCE, cyclic voltammetry (CV) showed a superior electrochemical response to the CAP concentration, while bare GCE and other modified GCEs showed an inferior electrochemical response. In addition, different concentrations, scanning rates, and pH electrolyte tests have been performed for MoN@S-GCN/GCE, which verified that it is an appropriate candidate for electrochemical detection of CAP. Differential pulse voltammetry (DPV) in the electrochemical determination of CAP exhibits a low detection limit of 6.9 nM and a sensitivity of 1.0557 μM μA–1 cm–2 for the current response, yielding a linear increase with increasing concentration of CAP from 0.5 to 2450 μM. Moreover, the proposed sensor shows appreciable selectivity and satisfactory recovery for real samples of milk and eye drop solutions.

Synthesis procedure of a Mn@FeNi-S/GO nanocomposite and its characterization and electrocatalytic performance.

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A nanocomposite containing palladium nanoparticles embedded on bismuth sulfide nanorods (Pd@Bi2S3) was synthesized based on a solvothermal method. The structural features, composition, and morphology were characterized by XRD, FT-IR, FE-SEM-EDS, FE-TEM, HAADF-STEM, XPS, N2 physisorption, and UV–vis. Further electrochemical measurements by EIS, CV, DPV, and LSV techniques were done. It revealed that Pd@Bi2S3/GCE were exploited as electrochemical sensors for the detection of toxic mercuric ions (Hg2+), which provides a wide linear range of 0.049–445 μM, excellent sensitivity of 1.17 μA μM–1 cm–2, and detection limit of 13.5 nM. The modified electrode has also been successfully applied for the detection of Hg2+ in sea fish, river fish, and water samples. The Pd@Bi2S3/GCE signifies a robust, usability, and highly effective method for trace level detection of Hg2+ ions. Furthermore, these Pd@Bi2S3 bifunctional catalysts were discovered to have good photoreduction activity for Hg2+ ions upon the visible-light irradiation.