Preparation of Hierarchical Pt/Pd-PEDOT/NGE Nanocomposites for High Caffeic Acid Electrochemical Sensing Performance

In this paper, Pt/Pd-poly(3,4-ethylenedioxythiophene)/nitrogen doped graphene (Pt/Pd-PEDOT/NGE) nanocomposites with hierarchical structure were prepared via a one-pot method. In the first step, Pd-PEDOT composites with Pd nanoparticles scattered on the surface or embedded in coralloid PEDOT particles were obtained through the redox reaction between PdCl42- and 3,4-ethylenedioxythiophene (EDOT) monomer. NGE was then added to improve the electrical conductivity and continuity of the nanocomposites. Finally, the added PtCl62- as well as the residual PdCl42- was reduced by ethanol through heating reflux. As a result, the Pt/Pd-PEDOT/NGE nanocomposites were obtained with Pt and Pd nanoparticles well-dispersed on the surfaces of PEDOT granules and NGE nanosheets. The obtained Pt/Pd-PEDOT/NGE nanocomposites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and Raman spectra. The electrochemical sensing performance of the Pt/Pd-PEDOT/NGE modified glassy carbon for caffeic acid (CA) was mainly studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under optimized conditions, Pt/Pd-PEDOT/NGE showed superior electrochemical sensing performance for detecting CA with the linear relationship ranging from 0.008 mu M to 46 mu M and a detection limit of 2.7 nM (a signal to noise ratio of 3 (S/N=3)). Moreover the nanocomposite also possesses high anti-interference capability and reproducibility. The real sample analysis of Pt/Pd-PEDOT/NGE was successfully carried out, implying the promising application of CA detection in food and beverages.