The Influence of Nickel Electrode’s Morphology on Glucose Detection

Different morphology metal nickel nanoelectrodes, such as nanospikes, layered nanosheets, layered flat particles, and hierarchical nanosheets, were synthesized on FTO glass via a hydrothermal method and utilized for glucose concentration determination in aqueous solutions under alkaline conditions. These electrodes demonstrated distinct electrochemical catalytic properties, such as surface area, mass transfer, and catalytic rate, during the glucose oxidation process. It was observed that a larger surface area can lead to a higher redox current in the absence of glucose, along with increased current noise and a prolonged response time when glucose is present. Despite having similar surface coverage, electrodes with a larger surface area can accommodate more Ni²⁺/Ni³⁺ redox couples, which generate a higher redox current in an alkaline solution. However, a poor catalytic rate for glucose can result in a low sensitivity of glucose detection. This implies that not all redox couples on the electrode surface actively participate in glucose oxidation, even when the electrodes have extensive glucose coverage and a higher density of redox couples. Moreover, a larger surface area can impede glucose diffusion, resulting in a longer response time during amperometric detection.

Graphical Abstract