Hierarchical and ultra-porous copper cobaltite flakes with honeycomb-like physiognomies for highly efficient non-enzymatic glucose sensing

Abstract

We present here a novel and facile synthesis of ultra-porous CuCo₂O₄ with an effort to increase the selectivity and sensitivity of innovative structured multi-metal oxides for electrochemical non-enzymatic sensing of glucose. The physicochemical characterization of the CuCo₂O₄ shows an ultra-porous flake-like microstructure with a honeycomb-like porous network and ideal stoichiometry of the elements. Thorough cyclic voltammetry and chronoamperometry studies show diffusion regulated glucose oxidation at ∼0.5 V (vs. Ag/AgCl) with an excellent sensitivity of 690 μA mM⁻¹ cm⁻², a linear range within 3.2 mM and a detection limit of 1.5 μM at a wide dynamic concentration range of glucose. As a promising and sensitive material for non-enzymatic electrochemical detection of glucose, this unique CuCo₂O₄ demonstrated remarkable selectivity to glucose even in the presence of large concentrations of other sugars and reducing agents. It also demonstrated excellent reproducibility and long-term stability for electrochemical glucose sensing. The unique microstructure with suitable pore architecture provides structural stability and maximum accessible electroactive surface for unhindered mobility of glucose as well as product molecules, resulting in improved sensitivity and selectivity of ultra-porous CuCo₂O₄ for glucose under non-enzymatic conditions. This study will boost the development of next-generation glucose sensors based on other ultra-porous non-noble metal oxide materials with similar electromicrostructural physiognomies.