The influence of nickel electrode's morphology on glucose detection

Different morphology metal nickel nanoelectrodes, such as nano spikes, layered nanosheets, layered flat particles, and hierarchical nanosheets were prepared on FTO glass by hydrothermal method, and were used to determine glucose concentration in aqueous solution under alkaline condition. All electrodes exhibit different electrochemical catalytic characteristics such as surface area, mass transfer, and catalytic rate in the progress of glucose oxidation. It was to note, larger surface area can produce a larger redox current in the absence of glucose, and a larger current noise, longer response time in the present of glucose. All of the electrodes have a similar surface coverage, and electrodes with larger surfaces have more Ni 2+ /Ni 3+ redox couples and yield more redox current in alkaline solution. However, poor catalytic rate for glucose can result in low sensitivity for glucose detection for electrodes. That means not all of the redox couples on the electrodes surface involved in the glucose oxidation, even if the electrodes have large glucose coverage and more redox couples. Furthermore, electrodes with a larger surface area have larger surface roughness, which decreases glucose diffusion and results in a longer response time in amperometric detection.