Nickel Hydroxide Nanoflowers for a Nonenzymatic Electrochemical Glucose Sensor

Abstract

Nickel hydroxide nanoflowers (f-Ni(OH)2) were synthesized in present work. The crystal structure of as-prepared sample is β-Ni(OH)2 phase (JCPDS # 14–0117). A nano composite film was fabricated by dispersing nano scale f-Ni(OH)2 and carbon nanotubes (CNTs) into Nafion solution. The electrocatalytic oxidation of glucose in alkaline medium on the f-Ni(OH)2-CNT-Nafion composite (fNCN) modified glass carbon electrode (GCE) had been investigated. The prepared f-Ni(OH)2-CNT-Nafion / Glass Carbon electrode (fNCN/GCE) glucose sensor could produce large electrocatalytic oxidation current in glucose solution when the applied potential exceeds 0.32 V vs. SCE, which is much lower than the similar sensor based on Ni(OH)2 nanosheets (s-Ni(OH)2) and is comparable to α-Ni(OH)2 sensor. Amperometric measurements were done with different concentrations of glucose. The fNCN/GCE glucose sensor has high sensitivity and low detection limit at a potential of 0.45 V (vs. SCE). It showed a detection limit of 0.5 μM (S/N = 3) and a sensitivity of 16.85 μA mM−1 (238.5 μA mM−1 cm−2) with a linear range from 0.1 to 1.1 mM. The Km derived from Lineweaver–Burk equation is evaluated to be 4.25 mM, which is much lower than enzymatic glucose biosensor.