Solid‐State Fabrication of Cu2O/CuO Hydroxide Nanoelectrode Array onto Graphene Paper by Thermal Dewetting for High‐Sensitive Detection of Glucose

Abstract

Nanostructures of Cu2O/CuO hydroxide suitable for the electrochemical determination of glucose are obtained by solid‐state dewetting of CuO layers 6, 8, and 31 nm thin deposited by sputtering onto 240 μm‐thick graphene paper. Solid‐state dewetting in nitrogen produces a partial decomposition of CuO into Cu2O and Cu. X‐ray diffraction patterns reveal the presence of high‐index crystallographic facets, which are reactive and useful toward glucose oxidation to gluconolactone. Typically, morphology studied by scanning electron microscopy reveals faceted nanoparticles with an average size below 200 nm. X‐ray photoelectron spectroscopy shows that the nanostructure surfaces of Cu2O and metallic copper exposed to natural ambient are promptly reoxidized and hydroxidized to a mixture of CuO and Cu(OH)2. Electrochemical characterization in amperometric mode reveals linear response to glucose concentration in the range from 50 to 10 × 10−3 m, sensitivity up to 83 μA cm−2 mm −1, and limit of detection up to 3.6 × 10−6 m. Good combination of low cost and simplicity of preparation with low limit of detection, high sensitivity, and wide linear range makes the proposed electrodes suitable for a variety of applications ranging from health to food and beverage industries.