Non-enzymatic sensing of dopamine using a glassy carbon electrode modified with a nanocomposite consisting of palladium nanocubes supported on reduced graphene oxide in a nafion matrix

Palladium nanocubes (Pd-NCs) were deposited on a reduced graphene oxide (rGO) support and then applied to modify a glassy carbon electrode (GCE) to obtain a non-enzymatic electrochemical sensor for dopamine (DA). In a comparison made by using copper underpotential deposition and a stripping method, it is shown that the Pd-NCs are evenly loaded on rGO and hence provide a surface area that is 2.42 times larger than that of rGO-free Pd-NCs. The modified GCE displays enhanced catalytic activity in catalyzing the oxidation of DA, best at a working potential of 0.25 V (vs. Ag/AgCl (3 M KCl)). The GCE modified with rGO-supported Pd-NCs showed remarkable selectivity over uric acid and ascorbic acid, a sensitivity to DA of 0.943 μA∙mM−1∙cm−2, and a 7.0 μM detection limit (at an SNR of 3).