Electrochemical detection of glucose and nitrophenol using a novel CuMn-LDHs/r-GO nanocomposite

Layered double hydroxides (LDHs) are gaining interest in multifunctional materials due to their uniform metal ion distribution and ease of anion exchange, contributing to advancements in clinical, environmental, and food chemistry. In this study, Cu–Mn layered double hydroxides (CuMn-LDHs) were synthesized using a one-step co-precipitation method. The pristine LDHs cause aggregation and have limited conductivity. Due to these limitations, reduced graphene oxide (r-GO) was incorporated into CuMn-LDHs and CuMn-LDHs/r-GO nanocomposites were synthesized. Reduced graphene oxide having high surface area caused increased dispersion of CuMn-LDHs and prevented agglomeration. The CuMn LDHs and CuMn-LDHs/r-GO nanocomposites were characterized by using Fourier transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS), UV-Vis spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). The CuMn-LDH modified gold electrode (CuMn-LDHs/AuE) exhibited electrocatalytic behavior achieving a low detection limit (LOD) of 0.006 μM, with a wide linear range of 50 μM to 6 mM and a sensitivity of 52.28 μA mM⁻¹ cm⁻². The composite material showed superior performance as a CuMn-LDH/r-GO modified gold electrode (CuMn-LDHs/r-GO/AuE) exhibited good electrocatalytic glucose oxidation, achieving a low detection limit (LOD) of 0.96 nM, with a linear range of 50 μM to 8.6 mM along with a sensitivity of 339.7 μA mM⁻¹ cm⁻² for glucose and a very high sensitivity of 9668 μA mM⁻¹ cm⁻² for nitrophenol (NP). The future potential of these electrode materials to develop sensors is demonstrated by their outstanding quantitative performance, cost effectiveness, and ease of use in a one-step synthesis process.