Electrochemical fabrication of stalactite-like copper micropillar arrays via surface rebuilding for ultrasensitive nonenzymatic sensing of glucose

Abstract In this work, an ultrasensitive nonenzymatic amperometric glucose sensor was facilely constructed based on a novel stalactite-like copper micropillar array, which was fabricated by surface rebuilding of a smooth Cu electrode in a blank H 2 SO 4 electrolyte without using templates and precursor solutions. During repeated square wave potential pulse perturbation, the smooth surface of Cu electrode was reshaped into a thin film of aggregated nanoparticles, assembled microspheres and then stalactite-like Cu micropillar arrays consisting of layered irregular Cu nanoflakes through repeated electrodissolution/electrodeposition of Cu. This is similar to the natural formation processes of stalactites that involve repeated dissolution/precipitation of CaCO 3 . Moreover, the accompanying evolution of hydrogen bubbles led to the pillar arrays porous. Such micro/nanostructured Cu pillar arrays are beneficial both for surface reactions and for mass transport. The influence of pulse potential, pulse frequency, perturbation time, and electrolyte concentration on the electrocatalytic activity of the treated Cu electrode was investigated in detail. The Cu pillar arrays not only had better electrocatalytic activity for oxidation of glucose than the aggregated Cu nanoparticles and assembled Cu microspheres, but also showed excellent electrochemical performance in sensing glucose with a wide linear range (500 nM∼4.711 mM), short response time (5 s), ultrasensitivity (2432 μA mM −1  cm −2 ), low detection limit (190 nM), good anti-interference and anti-toxicity, long-term stability (over 4 weeks), and satisfactory quantification of glucose concentration in human serum.