Electrochemical Cycling-Induced Spiky CuxO/Cu Nanowire Array for Glucose Sensing

The glucose level is an important biological indicator for diabetes diagnosis. In contrast with costly and unstable enzymatic glucose sensing, oxide-based glucose sensors own the advantages of low fabrication cost, outstanding catalytic ability, and high chemical stability. Here, we fabricate a self-supporting spiky CuxO/Cu nanowire array structure by electrochemical cycling treatment. The spiky CuxO/Cu nanowire is identified to be a Cu core passivated by a conformal Cu2O layer with extruded CuO petals, which provides abundant active sites for electrocatalytic reaction in glucose detection. An interruptive potential sweeping experiment is presented to elucidate the growth mechanism of the spiky CuxO/Cu nanostructure during the potential cycling treatment. The spiky CuxO/Cu nanowire array electrode exhibits a sensitivity of 1210 +/- 124 mu A.mM(-1).cm(-2), a wide linear detection range of 0.01-7 mM, and a short response time (<1 s) for amperometric glucose sensing. The study demonstrates a route to modulate oxide phase, crystal morphology, and electrocatalytic properties of metal/oxide core-shell nanostructures.