In this study, bimetallic Pd–Au/PEDOT/graphene (Pd–Au/PEDOT/rGO) nanocomposites were facilely prepared in an aqueous medium by a one-pot method. In addition to the Pd–Au/PEDOT nanoparticles, dendritic bimetallic Pd–Au nanoclusters were also obtained in the composites, which were verified by transmission electron microscopy and element analysis mapping characterization. The morphology of the nanocomposites was greatly influenced by the molar ratio of the added metal salt precursors. X-ray photoelectron spectroscopy and X-ray diffraction analyses indicated the presence of synergism and electron exchange between the Pd–Au bimetallic nanostructures, which play an important role in the enhancement of the electrocatalytic activity of the composite toward the oxidation of caffeic acid (CA). Under optimized conditions, the Pd–Au/PEDOT/rGO modified glassy carbon electrode showed a wide linear range of 0.001–55 μM and a low detection limit of 0.37 nM (S/N = 3) for CA detection. These results provide valuable insight on the development of novel modified electrodes based on bimetallic graphene nanocomposites for high performance electrochemical sensors.
Pd–Au bimetallic nanoparticles were facilely prepared on Ni foil substrate via in-situ self-assembly in reverse microemulsion of water/Triton X-100/n-hexanol/n-hexane. The Pd–Au nanomaterials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). A homogeneous alloy structure of Pd–Au in the bimetallic nanoparticles is indicated by XRD analysis and TEM. The SEM results show that the resultant bimetallic nanoparticles disperse uniformly on Ni foil with a narrow size distribution. The apparent size of bimetallic nanoparticles deposited on Ni depends on the reaction time of self-assembly. The TEM results reveal that the Pd–Au bimetallic nanoparticles consist of smaller homogeneous alloy nanoparticles with an average diameter of 5.1 nm, size of which depends on the size of micro water droplets. The growth mechanism of the Pd–Au nanoparticles in microemulsion was also explored. The electrocatalytic performance of the Pd–Au NPs/Ni electrode was studied by cyclic voltammetric and chronoamperometric measurements. Electrochemical experiments show that the Pd–Au nanoparticles have good catalytic activity and good stability for ethanol oxidation in alkaline media.
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