In situ formation of reduced graphene oxide@Co3O4-N-doped carbon and its structure-function relationship for glucose sensing

Highlights: • In-situ synthesis of reduced graphene oxide@Co₃O₄-N-doped carbon jungle is proposed. • Such electrode material exhibits a unique structure based on nanosheets. • The structural and compositional advantages of ternary materials are considered. • Electrode exhibits excellent performance for non-enzymatic detection of glucose. • The sensitivity is 2563 μA mM⁻¹ cm⁻²; the detection limit is 50.4 nM. The coordination of multiple materials is an effective strategy to develop high-performance sensing material, which requires a profound understanding of the structure-function relationship between multiple materials. Herein, a novel electrode material that reduced graphene oxide@Co₃O₄-N-doped carbon (oxide@Co₃O₄-NC) jungle has been formed on the surface of indium tin oxide (ITO) by the proposed in-situ preparation method. The template-directed growth of zeolitic imidazolate framework-67 (ZIF-67) is performed in a confined preparation process. The oxide@Co₃O₄-NC/ITO electrode with a unique structure based on two-dimensional nanosheets is eventually fabricated by a pyrolysis process of precursor. Such oxide@Co₃O₄-NC/ITO electrode can be directly used as a working electrode to establish an electrochemical sensor. The non-enzymatic glucose sensor based on oxide@Co₃O₄-NC/ITO exhibits good performances including the sensitivity of 2563 μA mM⁻¹ cm⁻², the detection limit of 50.4 nM, and the linear detection range of 0.5 μM–20.0 μM (R = 0.9992). The performance benefits of oxide@Co₃O₄-NC have been considered to be attributed to the structural and compositional advantages of ternary materials. This work represents the structure-function relationship of rGO, Co₃O₄ and NC, which is helpful for the design of multiple materials.