In-situ phenylhydrazine chemical detection based on facile Zr-doped MoS₂ nanocomposites (NCs) for environmental safety

Various concentrations (2.5, 5, 7.5, 10 wt%) of zirconium were doped onto MoS₂ using hydrothermal method. X-ray diffraction affirmed existence of hexagonal phase and increased crystallite size upon doping. Synthesized nanosheets appeared agglomerated after doping. Raman analysis provided evidence about defect density, layered structure of S-Mo-S planes as well as electronic band configuration of Zr-doped MoS₂. Furthermore, Zr-doped MoS₂ nanosheets were applied on a glassy carbon electrode as a layer of sensor film using nafion adhesive to fabricate the working electrode of the proposed phenylhydrazine (PHyd) electrochemical sensor probe. A calibration curve based on concentration of PHyd versus current plot was recorded to be linear over the full concentration range of 0.1 nM to 1.0 mM. The concentration linear range (0.1 nM–0.1 mM) was denoted as the large dynamic range (LDR) for PHyd detection based on the measurement of calibration plot. The slope of LDR with active surface area (0.0316 cm²) of GCE was used to determine analytical parameters of the sensor such as sensitivity (13.4652 µA µM⁻¹ cm⁻²), linearity, and detection limit (91.54 ± 4.58 pM). Besides these, the PHyd sensor performance was investigated in terms of reproducibility, long-term stability, response time, and validity with regard to its capability for effective analysis of real environmental samples in this field. All parameters exhibited satisfactory and acceptable results.