Ultra-sensitive Detection of Hg2+ in Water Using Flower-like Metallic 1T Tungsten Disulfide

The development of an electrochemical sensors for mercury ion (Hg2+) with ultratrace sensitivity, wide linear detection range (LDR), and high selectivity is still challenging. An electrochemical sensor based on flower-like metallic 1T phase tungsten disulfide (WS2) for sensing Hg2+ has been presented. The resulting sensor showed an excellent sensitivity toward Hg2+ with a wide LDR of 1 nM - 1 mM. Besides, the sensor exhibited an ultra-low detection limit down to 79.8 pM (pico molar) toward Hg2+, which is well below the safety limit of Hg2+ in drinking water recommended by the World Health Organization. Further, the sensor exhibited high selectivity for Hg2+ in presensce of different interferring metal ions such as Pb2+, Cu2+, Fe3+, Cr3+, Ag+, Sn2+, and Cd2+. The obtained superior sensing performance can be ascribed to the large surface area, flower-like morphology, high conductivity of WS2, and the complexation of Hg2+ ions with S2-. Thus it is suggested that the sensor is a potential device for real applications.

This work was financially supported by the Economic Development Administration University Center (ED18DEN3030025), National Science Foundation, and Major Research Instrumentation (NSF-MRI) (Grant 1428992), and NSF Innovation Corps (1906755).