Au nanoparticles anchored on Ni(OH)2 nanowires with multiple cavities for selective electrochemical detection of dopamine

Au nanoparticles supported on nickel hydroxide nanowires with multiple cavities (Au/m-Ni(OH)2) were synthesized and used for the enhanced electrochemical sensing of dopamine (DA). m-Ni(OH)2 nanowires were first fabricated based on an anion exchange strategy and then chosen as supports for Au nanoparticles without an additional stabilizer and surfactant. The morphology and composition of the nanocomposites were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS). TEM observations revealed that Au nanoparticles were uniformly embedded in the cavities of m-Ni(OH)2 nanowires, with a high dispersion and a narrow size of 2 nm. Electrochemical investigations indicated that the as-prepared sensor exhibited fascinating performance towards the oxidation of DA. The linear range for DA detection was 0.45 μM to 1.78 mM with a low detection limit of 0.09 μM (S/N = 3). Additionally, the DA sensor possessed an excellent selectivity in the presence of potentially interfering substances such as ascorbic acid (AA), uric acid (UA) and glucose (Glu). Therefore, it is expected that Au/m-Ni(OH)2 nanocomposites could be used as electroactive materials for developing DA sensors.