Hexagonal Co3O4 anchored reduced graphene oxide sheets for high-performance supercapacitors and non-enzymatic glucose sensing

Abstract

Reduced graphene oxide (RGO) incorporated onto metal-organic framework (MOF)-derived Co3O4 hexagons is prepared via a hydrothermal route for supercapacitor and glucose sensor applications. Various analysis techniques demonstrate that the Co3O4 hexagons were uniformly spread over the thin graphene sheets to assist the electron accessibility of the electrode materials. Under optimized conditions, using 0.1 M KOH electrolyte at a current density of 4 A g(-1), a specific capacitance value of 1300 F g(-1) is obtained. The fabricated asymmetric supercapacitor cycled reversibly and exhibits high energy and power density values of 65.8 W h kg(-1) and 2048 W kg(-1), respectively, over the voltage range of -0.1 V to 0.4 V. The asymmetric supercapacitor shows 80.5% capacitance retention even after 5000 cycles at a current density of 4 A g(-1), which indicates its high cycling stability in view of the fact that it is binder-free. Furthermore, the RGO-Co3O4 hexagon-modified electrode was optimized to realize the reliable amperometric determination of glucose concentration with a very low detection limit and excellent sensitivity value of 0.4 mu M and 1.315 mA mM(-1) cm(-2), respectively. All of these remarkable performance indicators suggest that RGO-Co3O4 is a promising electrode material for next-generation energy storage devices and electrochemical sensors.