Electrochemical non-enzymatic urea sensing using polyvinylpyrrolidine derived highly electrocatalytic NiCo2O4 nanowires

It is highly desirable to use non-enzymatic urea sensors in the clinical, biomedical, agricultural, and food industries. Thus, we have utilized polyvinyl-pyrrolidine (PVP) to tune the shape, particle and electrochemical properties of NiCo2O4 nanowires during hydrothermal processes. NiCo2O4 nanowires were investigated under alkaline conditions 0f 0.1 M NaOH in relation to their electrochemical activity in detecting urea using PVP. NiCo2O4 nanowires were analyzed using different analytical techniques to determine their structure, chemical composition, and crystallinity. The PVP has strongly changed the morphology of NiCo2O4 from nanorod to thin nanowires with diameter of 150 nm to 250 nm and the grain size was also reduced. A cubic phase crystal system displayed a typical spinel structure in NiCo2O4 nanowires. NiCo2O4 nanowires prepared with 50 mg of PVP show a wide linear range of urea concentrations between 1 and 16 mM with a limit of detection of 0.01 mM. In addition to this, the stability, selectivity, and reproducibility of the experiment were all satisfactory. Consequently, NiCo2O4 nanowires may perform better because they have a smaller particle size, a smaller grain size, are exposed to more catalytic sites, and have a higher electrical conductivity. The newly developed NiCo2O4 nanowire-bussed enzyme-free sensor was also examined for practicality.