▎ 摘　　要

The authors describe the fabrication of a 3-dimensional interconnected edge-exposed graphene nanostructure. It was fabricated by single-step chemical vapor deposition of highly foliated graphene on a network of gamma-alumina nanofibers having a single fiber diameter of around 7 nm. It is shown that a highly sensitive electrochemical sensor can be prepared for simultaneous detection of ascorbic acid, uric acid and dopamine from such graphene-coated nanofibers possessing different but controllable density of foliates. The study concentrates on the determination of ascorbic acid in a concentration range that extends from as low as 5 nM to 1 mM. The electrochemical properties of the materials were studied by cyclic voltammetry, chronoamperometry and differential pulse voltammetry using hexacyanoferrate as a redox probe. Response is linear in the 1 mu M to 60 mu M ascorbate concentration range, the sensitivity is 1.06 mu Aai...mu M(-1)ai...cm(-2), and the detection limit is 117 nM at foliate density of 50 foliates mu m(-1). The sensor was successfully applied to the determination of ascorbic acid in spiked urine samples. These results demonstrate a method for controllable growth of graphene possessing tailored morphology. In our perception, the application of such graphene-decorated nanostructures paves the way to the design of ultrasensitive electrochemical sensors of high stability.