Preparation of the mixture of graphene nanosheets and carbon nanospheres with high adsorptivity by electrolyzing graphite rod and its application in hydroquinone detection

In this work, a mixture of carbon materials was prepared by simple and fast method based on electrolyzing graphite rod in KNO3 solution under the constant current. The transmission electron microscope (TEM) indicated that the mixture was comprised of graphene nanosheets and carbon nanoparticles, and some carbon nanoaprticles were adsorbed on the surface of graphene nanosheet. The mixture modified glassy carbon electrode showed excellent catalytic and adsorptive ability towards the redox of hydroquinone (HQ). The effect factors, such as pH, scan rate, accumulation time and accumulation potential, were optimized. The chronocoulometry investigation demonstrated that the mixture can effectively increase the electrochemical active surface. Under the optimal determination conditions, the oxidation peak current was proportional to HQ concentration in the range of 0.1–100 and 100–600 μM. The detection limit was estimated to be 0.01 μM (S/N = 3). The developed electrode was further applied to determine HQ in soil samples with satisfactory results.