Fast conversion of redox couple on Ni(OH)2/C nanocomposite electrode for high-performance nonenzymatic glucose sensor

To pursue high performance for nonenzymatic glucose sensor, fast conversion of redox couple (Ni(OH)2↔NiOOH: NiII/NiIII) was established on Ni(OH)2 nanoparticles modified carbon (Ni(OH)2/C) composite electrode coupling with concentrated hydroxide electrolyte. The electrode was prepared by in situ precipitation of nano-Ni(OH)2 on carbon and then treated by cyclic voltammetry. Cyclic voltammetry was also used to identify the extremely high conversion rate of NiII/NiIII on the prepared composite electrode. Continuous cyclic voltammetry method with increasing the concentration of glucose on each cycle step by step was employed to promptly determine linear range and appropriate potential for glucose detection in 0.1, 1, and 7 M KOH electrolyte. The amperometric measurement under the optimized condition (0.28 V vs. saturated calomel electrode (SCE) in 7 M KOH) showed that the Ni(OH)2/C composite electrode exhibits a sensitivity of 1004.6 μA mM−1 cm−2 in a wide linear range from 1 μM to 15 mM (R = 0.9999). What is more, favorable selectivity, reproducibility, and stability for glucose detection were also obtained. These performances indicated that the proposed Ni(OH)2/C nanocomposite sensor with fast conversion of redox couple is a promising nonenzymatic glucose sensor.