MoS2@MWCNT modified glassy carbon electrode for electrochemical mercury(<sc>ii</sc>) ion sensors

Mercury (Hg2+) sensors play a crucial role in monitoring the quality of drinking water and ensuring that the concentration of Hg2+ ions remains within the permissible limits set by the World Health Organization (WHO). This study introduces a carefully fabricated electrochemical sensor that can accurately detect Hg2+, with high selectivity and sensitivity. The sensor utilizes cyclic voltammetry (CV) to accurately measure Hg2+ concentrations. An advanced composite electrode is fabricated by combining multi-walled carbon nanotubes (MWCNT) and MoS2 on a glassy carbon electrode (GCE) substrate, which functions as the sensing element. The interaction between MWCNT and MoS2 enhances electron transfer kinetics at the electrode interface, leading to faster reactions. These results show a significant 32-times increase in the peak current response for Hg2+ reduction compared to the bare GCE. As a result, the sensor can achieve a low detection limit (LoD) of 2 nM, surpassing the strict safety standards set by the WHO for Hg2+ in water. In addition, the fabricated electrode shows exceptional selectivity towards Hg2+. There are very few changes in the current when different heavy metal ions, such as Pb2+, Co2+, and As3+, are present. In addition, the sensor demonstrates exceptional repeatability, reproducibility and stability, showcasing its great promise for real-world use in monitoring the environment and conducting advanced chemical analysis.