Green and facile preparation of self-supporting nanoporous gold electrode and effect of ionic liquids on its electrocatalytic oxidation toward glucose

Abstract

Green and facile fabrication of self-supporting nanoporous gold electrodes (NPGE) was successfully achieved in an air/water-stable Lewis acid ionic liquid [Choline]Cl·2ZnCl2 via electrochemical method. In this medium, the effects of the scan cycle at different temperatures on the preparation process were investigated firstly. It was found that the Au–Zn alloy and porous structure could be formed at the temperature as low as 50 °C after five cycles and at 90 °C only after one cycle, indicating the easier formation of the porous structure in the present ionic liquid than that in the reported solvents. The porous structure was formed directly on the gold surface and the NPGE could catalyze the oxidation of glucose without any modification or covered film. The electrocatalytic ability of the NPGEs for glucose oxidation was evaluated in the neutral and alkaline solutions. Ionic liquids were correlated closely with the dissolution and conversation of glucose. The effect of three ionic liquids (choline acetate, 1-butyl-3-methylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium chloride) on the conversation of glucose on the NPGE was studied. These ionic liquids had great influence on the electrochemical signal of glucose and inhibited the catalytic ability of the NPGE. Glucose was electrochemically detected on the best NPGE in neutral medium finally. This work introduced a green and facile method for the fabrication of the self-supporting NPGE, expanded the application of gold nanomaterials in the electrocatalysis for glucose and provided a scientific support for the effect of ionic liquids on the conversation of glucose.