A sensitive enzyme-free electrochemical sensor composed of Co₃O₄/CuO@MWCNTs nanocomposites for detection of L-lactic acid in sweat solutions

L-Lactate acid (L-LA) is an important organic biomolecule and exists in human sweat thus making direct detection by current techniques challenging. It is thus important to develop a non-enzymatic L-LA sensor with high sensitivity and low cost. Herein, multidimensional mutli-walled carbon nanotube nanocomposites (Co₃O₄/CuO@MWCNTs NCs) incorporated with copper and cobalt oxide are prepared on nickel foam (NF, Surface area = 1 cm²) hydrothermally for L-LA detection. The Co₃O₄/CuO@MWCNTs NCs are analyzed by powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Ultraviolet–visiblespectroscopy (UV–VIS). Experimental results show that as an enzyme-free L-LA sensor, the Co₃O₄/CuO@MWCNTs NCs constitute a simple and low-cost detector to monitor L-LA in human sweat and the materials which yield high sensitivity and selectivity have broad prospects in the medical and health fields.