Preparation of electro-reduced graphene oxide supported walnut shape nickel nanostructures, and their application to selective detection of dopamine

A selective and sensitive method is reported for the detection of dopamine (DA) by using electro-reduced graphene oxide (er-GO) supported walnut shape nickel nanocomposite (er-GO-Ni) modified glassy carbon electrode. The surface morphological characterizations reveal that the Ni nanoparticles were homogeneously distributed on the er-GO nanosheets. Subsequently the electrochemical study shows an excellent selectivity, reproducibility, low detection limit (10 +/- 0.03 nM), high sensitivity (23.3 nA center dot mu M-1), and reasonably wide linear range (0.05-50 mu M) for the detection of DA at +0.1 V vs SCE. The selectivity for DA over ascorbic acid and uric acid is attributed to the charge-based discrimination of the modified electrode. An excellent correspondence of calculated and reported rate constant for the DA oxidation is also obtained by hydrodynamic experiments using a rotating disk electrode.