A facile green synthesis of graphene/AuNP/PEDOT:PSS nanocomposite and its application in electrochemical sensor

A facile and green chemical method was developed to prepare a graphene/gold nanoparticle/PEDOT:PSS nanocomposite. Firstly, graphene (GP) was prepared by electrolytic exfoliation of graphite in an aqueous polystyrene sulfonate... [ view full abstract ]

A facile and green chemical method was developed to prepare a graphene/gold nanoparticle/PEDOT:PSS nanocomposite. Firstly, graphene (GP) was prepared by electrolytic exfoliation of graphite in an aqueous polystyrene sulfonate (PSS) solution. After adding HAuCl₄ and EDOT monomer to the GP/PSS dispersion, gold nanoparticles and PEDOT were formed simultaneously via in-situ reduction of HAuCl₄ and oxidative polymerization of EDOT. The resulting as-prepared GP/AuNP/PEDOT:PSS dispersion was drop-casted on a glassy carbon electrode (GCE) and the resulting electrode was then used to detect dopamine (DA) and uric acid (UA). The morphology and structure of the nanocomposite were characterized by a transmission electron microscope (TEM), a scanning electron microscope (SEM), Raman spectroscopy, FTIR spectroscopy and X-ray diffraction (XRD). In comparison to a bare GCE, the graphene/AuNP/PEDOT:PSS modified electrode showed considerably higher electrocatalytic activities toward the oxidation of dopamine (DA) and uric acid (UA) with an increase in peak currents and a decrease in electrode overpotentials. Moreover, the oxidation of a common interfering agent such as ascorbic acid (AA) could be greatly suppressed by the resulting modified electrode. Using differential pulse voltammetry (DPV), selective determination of dopamine and uric acid in the presence of ascorbic acid could be achieved with a peak potential separation of 110 mV between DA and UA. The sensor exhibited wide linear responses for DA and UA in the ranges of 1 nM to 300 μM and 10 μM to 1 mM with detection limits (S/N = 3) of 100 pM and 10 μM, respectively. The established sensor showed excellent reproducibility and high stability over at least 2 months without any significant change in its electrochemical response. There was also no electrode fouling observed, even after 25 successive scans. Furthermore, the proposed sensor was successfully used to determine DA and UA in real samples with satisfactory recovery results.