Solvothermal synthesis of sphere-like CuS microcrystals and improvement as nonenzymatic glucose sensor

In this article, we report the obtention of sphere-like copper sulfide (CuS) microcrystals with 3–5 μm diameter on a large scale by the solvothermal approach, which is simple, facile, and effective. The as-prepared products are well characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD), indicating that the sphere-like CuS microcrystals are composed of nanosheets with the uniform thickness of about 50 nm and have good morphology and high purity. The factors influencing the formation of the sphere-like CuS microcrystals are investigated in detail using SEM characterizations. Specially adjusting the quantity of thiourea can effectively control the formation of the flower-like, sphere-like, or irregularly spindle-like CuS microcrystals built by nanosheets. Based on the “oriented attachment mechanism,” CuS nanosheets are aligned with one another and point toward the spherical center, and further construct the sphere-like CuS microcrystals. The electrocatalytic oxidation of glucose in alkaline medium at the sphere-like CuS microcrystal-modified electrode has been monitored by cyclic voltammograms (CVs). Compared to the bare glassy carbon electrode, a couple of obvious redox peaks and the improved peak currents toward the glucose redox are examined at the sphere-like CuS sensor with the sensitivity of 117.3 μA cm⁻² mM⁻¹. The high electrochemical activity, good repetition, and stability indicate that the sphere-like CuS sensor has the potential application in the nonenzymatic glucose sensor.