Synergistic ternary MnO/(rGO@Ag) nanocomposites for sensitive electrochemical dopamine detection.

The development of high-performance electrochemical sensors is vital for the accurate and sensitive detection of neurochemicals such as dopamine (DA), a critical biomarker for neurological disorders. In this study, we report the fabrication of a novel ternary nanocomposite (MRA-10), composed of MnO nanosheets (NSs), silver nanoparticles (Ag NPs), and reduced graphene oxide (rGO). The nanocomposite was synthesized a hydrothermal process followed by sonochemical integration and applied as a sensing layer on a glassy carbon electrode (GCE). Among the tested variants, MRA-10 (with 10 wt% rGO@Ag) exhibited the best electrochemical performance because of the synergistic interaction of the high surface area of MnO, the excellent electrical conductivity of rGO, and the catalytic activity of Ag. Structural analyses confirmed a uniform Ag distribution and a strong interfacial contact between the components. Electrochemical studies using EIS, CV, and DPV revealed a remarkably low charge transfer resistance (178.45 Ω), high electroactive surface area (0.0803 cm), and superior sensitivity of 353.20 μA μM cm. The sensor demonstrated a broad linear range (10-500 μM) and a low detection limit (0.2615 μM) for DA, with excellent reproducibility (RSD = 1.41%) and long-term operational stability. The DA oxidation mechanism followed a two-electron adsorption-controlled process. This study introduces a robust, scalable, and cost-effective electrode platform for neurotransmitter sensing with promising clinical and environmental diagnostic applications.