Development of sensitive electrochemical sensor Ni@CuO/rGO/PtE for the determination of 4-Nitrophenol: An electroanalytical approach for pollution control

Abstract

Para nitrophenol, generally known as 4-nitrophenol (4-NP), is a well-known organic pollutant that is being broadly discharged into the environment and poses several health threats to humans. For the sensitive and selective screening of 4-NP, a new electrochemical sensor based on Ni@CuO/rGO/PtE has been developed. The XRD analysis revealed excellent crystalline structure with an average size of 47.3 nm for Ni@CuO/rGO nanocomposite. SEM and HR-TEM characterization evaluated the successful incorporation of Ni and CuO into the GO sheets. The EDX analysis confirmed the prepared nanocomposite's exceptional purity and percent elemental composition. The prepared material was casted on the surface of bare PtE via the drop-casting method, which resulted in the uniform deposition of Ni@CuO/rGO over the PtE's surface. The fabricated sensor Ni@CuO/rGO/PtE manifested excellent response for 4-NP under optimized conditions, e.g., scan rate 110 mV/s, PBS electrolyte acidic pH -5, and under potential window between (−0.3 to −1.2 V). A broad linear concentration range was optimized from 0.09 to 105 μM to get a linear calibration curve of 4-NP. The LOD and LOQ of the proposed method were calculated as 0.0054 μM and 0.018 μM, which is almost lower than the reported sensor for 4-NP. The analytical applicability of Ni@CuO/rGO/PtE was tested in tap water and river water samples. The fabricated sensor exhibited acceptable recoveries for 4-NP in water samples, highlighting the proposed sensor's good reliability in real samples.