Nickel oxide (NiO) nanostructures modified by rice straw extract phytochemicals for efficient urea oxidation in alkaline media using non-enzymatic sensing

Generalized illustration of urea oxidation on the surface of NiO nanostructures into CO2, N2 and H2O. [Display omitted] •Rice straw extract has dynamically changed the surface properties of NiO nanostructures.•A non-enzymatic sensing activity of NiO nanostructures was demonstrated.•Surface modified NiO exhibited wide liner range of urea sensing from 0.1 mM to 19 mM.•A high selectivity, reproducibility and stability of NiO nanostructures were observed.•An excellent real time application for urea detection was found. For non-enzymatic urea sensing, there is a need for an electrocatalytic material that is highly efficient, but it is difficult to synthesize in an environmentally friendly, economical, easy, and scalable manner. Consequently, an electrode containing nickel oxide (NiO) nanostructures modified on glassy carbon was developed for use in non-enzymatic urea oxidation. NiO nanostructures were prepared using rice straw extract in addition to conventional chemical methods. An analysis of NiO nanostructures was carried out using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–visible spectroscopy, and Fourier transform infrared spectroscopy (FTIR). A variety of electrochemical measurements were performed on NiO samples prepared in 0.1 M NaOH aqueous solution, including cyclic voltammetry, linear sweep voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. It was confirmed that these NiO samples possessed excellent redox properties. As compared to catalytic reactions for the urea oxidation reaction, electrochemically mediated Ni(III) species have demonstrated superior performance on the modified electrode surface. A number of characteristics have been reported for the NiO modified electrode. These characteristics include excellent stability, fast response times, a low detection limit of 0.004 mM, a wide linear range of 0.1 mM–19 mM in urea concentration, good selectivity, decent reproducibility, and promising performance in real-world situations. NiO modified electrodes exhibit enhanced activity due to rapid charge transfer, enriched surface active sites, large surface areas, and high electrode compatibility. The findings suggest that rice straw extract could be used as an alternative raw material for the fabrication of next-generation electrodes.