Electrochemically Exfoliated WS₂ Nanosheets for the Electrochemical Impedimetric Detection of NADH

In this work, exfoliated WS₂ nanosheets were synthesized using a two-electrode-configured electrochemical exfoliation method and they were used as a potential material for the detection of NADH. Using screen-printed carbon electrodes (SPCEs) as a sensing platform, exfoliated WS₂ nanostructures (ex-WS₂) were drop-casted and their electrocatalytic activity was studied in the presence of NADH. The electrochemical impedance spectroscopy (EIS) was applied as a sensing tool to achieve superior sensing performance towards NADH. At the optimized DC bias value of 0.4 V, the developed NADH sensor shows linear calibration plots in the ranges of 2 to 2048 μM. From the calibration data, the sensitivity value was found to be 36.875 Ω log([NADH])⁻¹ with the limit of detection (LOD) value of 57 nM. In addition to that, it also exhibited very high selectivity in the presence of other possible interfering species, suggesting that the present exfoliated WS₂-modified SPCE-based sensing platform could be used for the impedimetric label-free monitoring of NADH in various fields.