Hydrothermal Synthesis of Cr₂Se₃ Hexagons for Sensitive and Low-level Detection of 4-Nitrophenol in Water

We report a simple hydrothermal method used for the synthesis of Cr₂Se₃ hexagons (h-Cr₂Se₃) and its application towards electrochemical sensing of 4-nitrophenol (4-NP). The formation of h-Cr₂Se₃ was confirmed by using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The electrochemical activity of the h-Cr₂Se₃ modified screen-printed carbon electrode (SPCE) towards 4-NP was studied using cyclic voltammetry (CV) and amperometric i-t techniques. Typically, the obtained results were compared with those for a bare SPCE. The CV result clearly reveals that h-Cr₂Se₃ modified SPCE has higher catalytic activity towards reduction of 4-NP than bare SPCE. Hence, h-Cr₂Se₃ modified SPCE was concluded as a viable sensor for sensitive determination of 4-NP. Under optimized conditions, h-Cr₂Se₃ modified SPCE demonstrates the excellent capacity to detect the 4-NP in a linear range from 0.05 µM to 908.0 µM. The LOD and sensitivity in detection of 4-NP were determined at 0.01 µM and 1.24 µAµM^-1 cm^-2 respectively. The sensor is highly selective and stable and shows reproducible recovery of 4-NP in domestic supply and river water samples.