Preparation and Electrical Sensing Performance on Glucose of Arch Bridge-Like NiO/Carbon Paper Electrode

When constructing an enzyme-free glucose sensor using nano NiO, the nano NiO tends to agglomerate, causing the decrease in the specific surface area and electrical sensing performance of the electrode. Therefore, research mentioned by the title was conducted. Nano NiO was modified on carbon paper (CP) using the constant potential method. With the obtained NiO/CP electrode as the working electrode, the platinum plate as the auxiliary electrode, and the calomel electrode as the reference electrode, glucose was quantitatively detected using Ampere current-time (I-t) method in 0.1 mol·L⁻¹ sodium hydroxide solution. As found by results from SEM characterization, the nano NiO on the synthesized NiO/CP electrode had an arch bridge shape and a layered stacking structure on its surface, which was conducive to increasing the specific surface area of the electrode and the active sites on the surface. As found by results from EDS characterization, the electrode contained C, Ni, and O elements, indicating that nano NiO had successfully combined with CP referring to the SEM image. As found by results from the cyclic voltammetry, the current absolute value of the oxidation/reduction peak continuously increased/reduced and moved towards high/low potential with the increase of glucose concentration, respectively, and the electrocatalytic process of the electrode on glucose was mainly controlled by diffusion. As found by results from the I-t method at a detection potential of 0.50 V, the response time of the electrode to glucose was about 10 s. The absolute value of current density increased step by step with the increase of glucose concentration, and linear relationships between the absolute value of current density and glucose concentration were found in the ranges of 0.000 5-0.71 mmol·L⁻¹, 0.71-4.71 mmol·L⁻¹ and 4.71-12.21 mmol·L⁻¹. The electrode had good reproducibility, repeatability, and anti-interference ability. The method was used for the analysis of 5% (mass fraction) glucose injection, and the determined value of glucose was 96.44% of the theoretical value, and RSD was 4.0% after 5 repeated determination.