Fabrication, characterization and application of gold nano-structured film

A straightforward, rapid and “green” approach was proposed for the fabrication of gold nano-structured films. A gold electrode was firstly oxidized under a high potential of 10 V, and β-d-glucose, as a nontoxic reducing agent, was then chosen to reduce the gold oxide. This process gives a fractal gold nanofilm on the top of the gold electrode in a way of completely “green” chemistry. X-ray photoelectron spectroscopy, atomic force microscopy, scanning electron microscopy and electrochemical methods were adopted to characterize the as-prepared gold nanofilm. The gold nanofilm was found to have abundant adatom state Au∗, evidenced by the electrochemical process of Au∗/Au∗OHads couple. The as-prepared gold nanofilm greatly facilitates the electrochemical oxidation of glucose in neutral solutions. As the gold nanofilm was formed in situ on the gold electrode, additional immobilization procedures are not necessary. A sensitive enzyme-free sensor can be easily developed for the detection of glucose in pH 7.4 phosphate buffer solution, which gives linear ranges up to 57.5 and 30 mM with detection limits down to 0.75 and 3.6 μM at potential of +0.3 and −0.15 V, respectively. A rapid response for glucose could be achieved in less than 2 s. At a detection potential of −0.15 V, physiological interference agents such as ascorbic acid, uric acid and acetylaminophenol were efficiently excluded.