The Self-Adsorption of Ni Ultrathin Layer on Glassy Carbon Surface and Their Electrocatalysis toward Glucose

The Ni ultrathin layer was obtained by the simple self-adsorption of Ni2+ on the surface of glassy carbon electrode. Through a consecutive potential scan in alkali solution, the adsorbed Ni2+ was transformed to the ultrathin layer of Ni(OH)2/NiOOH which exhibits good electrocatalysis toward the oxidation of glucose. Only a little of Ni2+ was consumed to obtain such an ultrathin layer of Ni with excellent electrochemical performance. Due to the low diffusion hindrance and the good electrocatalytic property of Ni(OH)2/NiOOH ultrathin structure, the electrode response toward glucose reaches a steady-state level within only 4 s, demonstrating a rapid and sensitive response. The calibration plot is linear over the wide concentration range of 0∼7 mM with a slope of 1.01 μA/mM (sensitivity) and a correlation coefficient of 0.9996. The detection limit of the electrode was found to be 10.9 μM at a signal-to-noise ratio of 3. The adsorption method is very simple and the ultrathin layer of Ni was formed in a controllable manner with the size lower than nanoscale, which will find the potential applications in nanofabrication for the nanodevices of fuel cell or electrochemical sensor in the future.