Development of Palladium on Bismuth Sulfide Nanorods as a Bifunctional Nanomaterial for Efficient Electrochemical Detection and Photoreduction of Hg(II) Ions

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.