Yttrium Hexacyanoferrate Microflowers on Freestanding Three-Dimensional Graphene Substrates for Ascorbic Acid Detection

Recently, three-dimensional carbon nanostructures have attracted significant attention for biosensing applications. We have prepared highly porous three-dimensional graphene (3DG) structures (90% porosity) by template-assisted chemical vapor deposition technique and enhanced their electrocatalytic activity through in situ electrochemical deposition of rose-like yttrium hexacyanoferrate particles on their struts. The 3DG structure has an average channel size of 500 pm, and the microflowers have lateral sizes in the range of 2-10 mu m. The performance of the 3DG-based electrode in efficient detection of ascorbic acid was investigated after transferring on a gold screen printed electrode (SPE). The sensor exhibits an electrocatalytic response as low as <5 s, a detection limit of 0.5 pM within a wide linear range up to 1.5 mM, and a fairly high sensitivity of 43.3 mu A mu M-1 cm(-2). These electrochemical responses are superior to many other electrodes, particularly carbon materials, utilized for ascorbic acid detection. The developed sensor also shows good selectivity for ascorbic acid detection; no interference with other common electroactive inferences such as glucose, sucrose, and uric acid is obsereved. The potential application of the Y-modified 3DG sensor for detection of ascorbic acid in commercial juices as real samples is also shown. This novel nanocomposite structure may open a novel approach for the expansion of efficient electrochemical sensors based on commercial SPE.