Highly efficient non-enzymatic glucose sensor based on CuxS hollow nanospheres

Copper sulfide with copper to sulfur stoichiometric ratios of 2:1, 2.5:1 and 3:1 is rapidly synthesized by varying the amount of sulfur precursor against Cu2O nanospheres. The size, morphology, crystalline nature, and elemental compositions of CuxS hollow nanospheres such as, CuS, Cu2S, Cu7S4, and Cu2O are characterized by using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction analysis (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. The synthesized CuxS hollow nanospheres display a substantial electrocatalytic activity towards the oxidation of glucose in alkaline medium. Notably, the Cu7S4 hollow-like nanospheres exhibited highest glucose sensitivity of 3728.7 mu A mM(-1) cm(-2) as compared to the other CuxS hollow nanospheres. Further, the Cu7S4 hollow nanospheres show a wide linear concentration responses towards the oxidation of glucose from 1.0 mu M to 2.0 mM, with a limit of detection (LOD) of 0.023 mu M (S/N = 3). The obtained results indicate that Cu7S4 hollow nanospheres as a promising candidate for non-enzymatic glucose sensing.