Nickel Foam-Loaded CoFe₂O₄/CuS/RGO Electrode for a Bifunctional Device for Glucose Detection and Hydrogen Release

Bad living habits, such as the lack of exercise, unhealthy food consumption, and insufficient sleep, cause health problems such as reduced blood glucose regulation ability and early onset of diabetes. At the same time, the pursuit of sustainable development requires renewable energy generation, and water splitting driven by solar, wind, hydro, and geothermal power is one of the viable techniques. Therefore, a bifunctional nanoelectrode with dual functions of sweat analysis and the hydrogen evolution reaction (HER) is of great significance in the prevention of diabetes and the development of green energy. Herein, a CoFe₂O₄/CuS/RGO composite electrode is fabricated on nickel foam (NF with a surface area of 1 cm²) by simple digestion, chemical coprecipitation, and hydrothermal methods. The glucose redox and charge transfer processes have been systematically investigated. The results reveal that the composite not only has excellent glucose electrochemical activity but also can be used for hydrogen production. The detection boasts a glucose detection range of 1-5 mM, sensitivity of 1199 μA mM^-1cm^-2, signal-to-noise ratio of 3, and detection limit of 0.25 μM. As an electrode in a hydrogen evolution setup, it shows a current density of 10 mA cm^-2 at an overpotential of 327 mV and a Tafel slope of 10.27 mV dec^-1.