Fast synthesis of porous NiCo2O4 hollow nanospheres for a high-sensitivity non-enzymatic glucose sensor

In this paper, we report the fast synthesis of porous NiCo2O4 hollow nanospheres via a polycrystalline Cu2O-templated route based on the elaborately designed coordinating etching and precipitating process. The composition and morphology of the porous NiCo2O4 hollow nanospheres were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The electron-transfer capability and electrocatalytic activity of the materials were investigated by electrochemical impedance spectroscopy and cyclic voltammetry. NiCo2O4 was endowed with superior electron-transfer capability, large surface area, and abundant intrinsic redox couples of Ni2+/Ni3+ and Co2+/Co3+ ions; thus, the modified electrode exhibited excellent glucose-sensing properties, with a high sensitivity of 1917 mu A.mM(-1).cm(-2) at a low concentration, a good linear range from 0.01 mM to 0.30 mM and from 0.30 mM to 2.24 mM, and a low detection limit of 0.6 mu M (S/N = 3). (C) 2016 Elsevier B.V. All rights reserved.