Sensitive detection of urea based on Dy₂O₃-Co₃O₄@ZrO₂ nanocomposite by electrochemical approach for environmental assessment

This approach involved the wet chemical synthesis of Dy₂O₃-Co₃O₄@ZrO₂ nanocomposite (NC) for detecting as well as electrochemically hydrolyzing the hazardous substances in an aqueous solution. A comprehensive examination of the resultant material was carried out using advanced analytical techniques encompassing UV-DRS, FTIR, I-V, powder XRD, FESEM equipped with EDS, DPV, and HR-TEM, in addition to BET analysis, to investigate its optical, structural, elemental and morphological properties. After that, a novel electrochemical probe with high selectivity and sensitivity was tailored for urea, among other interfering chemicals, by modifying glassy carbon electrode (GCE) by applying a thin layer of Dy₂O₃-Co₃O₄@ZrO₂ NC. Within the modification of GCE, 5 % ethanolic nafion served as a conductive adhesive binder. Through a comparative analysis, it was found that our newly developed Dy₂O₃-Co₃O₄@ZrO₂-NC/Nafion/GCE was exceptionally sensitive towards urea and had long-term stability along with good affinity with it even in the presence of numerous interfering species. The slope of calibration curve was used to determine the key analytical parameters, such as sensitivity, limit of detection (LOD) and limit of quantification (LOQ), so as to optimize the above stipulated newly develop electrochemical probe. The analytical parameters, including LOD at signal-to-noise ratio (S/N) over 3, LOQ and sensitivity were found to be 0.0491 nM, 0.164 nM, and 19.47 µAµM⁻¹cm⁻², respectively, across linear dynamic range (LDR) ranging urea concentrations from 1.0 nM to 10.0 mM with r² value as 0.9680. As a result, this study also sheds light on cost-effectiveness and long-term stability of newly fabricated electrochemical probe, selective only for urea, in addition to its efficiency. Moreover, this study gives us an idea to effectively interrogate the various toxic chemicals in real samples by using a novel electrochemical, I–V, approach based on reported / non-reported different kind of semiconductor nanocomposite modified GCEs as selective electrochemical probes.