In situ growth of Ni/NiO on N-doped carbon spheres with excellent electrocatalytic performance for non-enzymatic glucose detection

A non-enzymatic potentiometric glucose sensor was developed by modifying a glass carbon electrode (GCD) with Ni/NiO decorated nitrogen doped carbon spheres (Ni/NiO/NCSs). The Ni/NiO/NCSs were prepared with in situ growth of Ni/NiO on the nitrogen doped carbon spheres. The morphology and composition of the materials were characterized by SEM, TEM, XRD and XPS, respectively. The Ni/NiO/NCSs modified GCD electrode exhibited higher current response than that of nitrogen free counterpart and NiO/nitrogen carbon spheres for non-enzymatic oxidation of glucose in alkaline media. The amperometric measurement revealed that the sensor had wide linear regions of 2 μM-600 μM and 800 μM-2500 μM with a sensitivity of 219.19 μA mM−1cm−2 and 87.88 μAmM−1cm−2 respectively. Moreover, the Ni/NiO/NCS composites also exhibited good selectivity by adding certain amount of urea, NaCl, l-proline, l-valine, l-Leucine and ascorbic acid into 0.1 M NaOH solution. The excellent electrocatalytic performance may be attributed to the synergistic effect of nitrogen doping and Ni loading, which may result in the increase of electron density and the enhancement of surface conductivity of the composite electrode materials.