Solvothermal method synthesized SnS nanoplates composites for electrochemical sensing of toxic ions Hg2+ and Pb2+

Tin sulfide (SnS) semiconductors have become emerging sensor materials for the electrochemical sensing of heavy metals in trace amounts due to their supportive electrochemical properties. This study reports the synthesis, characterization of SnS/rGO composites and sensing of mercury and lead ions in an aqueous solution. SnS/rGO composites with the proper loading of rGO concentration were synthesized using simple solvothermal method and applied for sensing the heavy metals of mercury and lead ions. The synthesized samples were characterized by XRD, FE-SEM, TEM, FTIR and Raman spectroscopy to study the structure and morphology of the samples. Cyclic voltammetry and AC impedance were used to characterize the samples for electrochemical detection of toxic metals Hg and Pb ions. The XRD analysis reveals that the average crystallite of SnS/rGO nanoplates is in the range of 56–67 nm and was confirmed by TEM. FE-SEM analysis reveals the formation of nanoplates on rGO sheets. Raman spectroscopy and FTIR analysis confirm the presence of rGO and the composition of the prepared sample. The electrochemical sensing of SnS and SnS/rGO nanoplates with graphite powder in 0.1 M KOH solution showed good reversibility and was applied for sensing of HgCl₂ and PbCl₂ with a quick response time of 2 s. The LOD for Hg and Pb ions was found to be 47.3–65.3 ppm, respectively. All the prepared electrodes of SnS and SnS/rGO composites could be effectively supported by the electrochemical sensing response to HM ions in alkali medium.