Ionic liquid-assisted in situ growth of a cobalt oxide composite and its application in supercapacitors and electrochemical biosensors

Abstract

Cobalt(II,III) oxide (Co₃O₄) nanorods/reduced graphene oxide (Co₃O₄ NR/RGO) composite has been successfully prepared via a reactable ionic liquid-assisted hydrothermal process and subsequent annealing. Here, the ionic liquid 1-hexadecyl-3-methylimid-azolium trifluoroacetate ([C₁₆MIM]CF₃COO) has been used as the template, co-solvent and reactant. Co₃O₄ NR/RGO can be used as the electrode material in supercapacitor applications and the non-enzymatic electrochemical detection of glucose. It has been found that the Co₃O₄ NR/RGO composite displays superior capacitive performance not only with high specific capacitance of 813.1 F g⁻¹ at a current density of 1 A g⁻¹, but also with excellent cycling stability. It can even detect glucose with a high sensitivity of 81.8 μA mM⁻¹ and a remarkable low detection limit of 67 nM (S/N = 3).