Metallic 1T Phase Tungsten Disulfide Microflowers for Trace Level Detection of Hg2+ Ions

Abstract Electrochemical sensors for mercury ion detection would ideally demonstrate wide linear detection ranges (LDRs), ultratrace sensitivity, and high selectivity. This work presents an electrochemical sensor based on metallic 1T phase tungsten disulfide (WS 2 ) microflowers for the detection of trace levels of Hg 2+ ions with wide LDRs, ultratrace sensitivity, and high selectivity. Under optimized conditions, the sensor shows excellent sensitivities for Hg 2+ with LDRs of 1 n m –1 µ m and 0.1–1 m m . In addition to this, the limit of detection of the sensor toward Hg 2+ is 0.0798 n m or 79.8 p m , which is well below the guideline value recommended by the World Health Organization. The sensor exhibits excellent selectivity for Hg 2+ against other heavy metal ions including Cu 2+ , Fe 3+ , Ni 2+ , Pb 2+ , Cr 3+ , K + , Na + , Ag + , Sn 2+ , and Cd 2+ . The thus‐obtained excellent sensitivity and selectivity with wide LDRs can be attributed to the high conductivity, large surface area microflower structured 1T‐WS 2 , and the complexation of Hg 2+ ions with S 2− . In addition to good repeatability, reproducibility, and stability, this sensor shows the practical feasibility of Hg 2+ detection in tap water suggesting a promising device for real applications.