Facile preparation of Pd–Au bimetallic nanoparticles via in-situ self-assembly in reverse microemulsion and their electrocatalytic properties

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.