Facile synthesis of Ni nanofoam for flexible and low-cost non-enzymatic glucose sensing

A novel Ni nanofoam electrode has been fabricated by low-cost methods and applied for non-enzymatic glucose sensing. Ni(OH)(2) nanowalls, prepared by room-temperature chemical bath deposition, were transformed into an ensemble of Ni nanoparticles (20-30 nm in size) upon annealing in forming gas at 350 degrees C, and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), temperature programmed reduction with hydrogen (H-2-TPR) and surface area measurements. The Ni nanofoam was converted to the catalytic Ni(OH)(2)/NiOOH - necessary for non-enzymatic glucose oxidation - by cyclic voltammetry (CV) in NaOH electrolyte. The electrode fabricated on conducting glass substrate showed a glucose sensitivity of 2.37 mA/cm(2)mM, a linear range of 0.01-0.7 mM, a limit of detection (LOD) of 5 mu M, a fast response time (1 s), and resistance to chloride poisoning. The glucose sensor also exhibited an excellent long-term stability (4% decrease in sensitivity after 64 days) and selectivity in the presence of common interfering species. The versatility of the preparation method was demonstrated in the fabrication of a flexible (plastic substrate) sensor with a sensitivity of 1.43 mA/cm(2)mM. The ease of fabrication and the excellent properties of Ni nanofoam in glucose sensing make it promising for low-cost and wearable sensing applications. (C) 2015 Elsevier B.V. All rights reserved.