Nickel Foam-Supported NiO/Cu-ZIF/GO for the Detection of Lactate in Sweat and Applications in Supercapacitors

With the growing demand for health monitoring, the development of non-invasive, real-time technologies to detect biomarkers in biofluids is crucial. This research develops a dual-functional electrochemical sensor, utilizing a three-dimensional porous nanocomposite of NiO/Cu-ZIF/GO, for the highly precise and selective measurement of lactate in sweat. The composite structure, comprising NiO nanoflowers, Cu-ZIF cubic frameworks, and ultrathin graphene oxide (GO) nanosheets, was successfully synthesized via solvothermal methods, magnetic stirring, and liquid-phase physical adsorption strategies. This material integrates the high catalytic activity of NiO, the microporous confinement effect of Cu-ZIF, and the conductive network of GO, achieving synergistic enhancement of lactate oxidation and energy storage. The electrochemical tests exhibited a sensitivity of 36.72 μA·mM⁻¹·cm⁻² and a detection limit of 0.354 mM, excellent anti-interference capability (against uric acid, ascorbic acid, etc.), and long-term stability (96.6% initial response retained after 30 days). In addition, the material shows a specific capacitance of 120 F g ⁻ ¹ (1A g<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup>) in the supercapacitor, and when the current density is 1A g<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup>, the specific capacitance is 93.6% after 5000 times of charge and discharge, which verifies its dual function characteristics.