Synthesis of PdAu 3:1/C nanoparticles using phase-transfer method for ethanol electro-oxidation

PdAu 3:1/C-1 and PdAu 3:1/C-2 nanoparticles were prepared in methylene chloride and water, respectively. The syntheses featured the use of tetrabutylammonium hydroxide as a phase-transfer agent and stabilizer. Electrochemical characterization showed that compared with PdAu 3:1/C-2, PdAu 3:1/C-1 had superior ethanol oxidation reaction (EOR) activity in alkaline media. The results of X-ray powder diffraction indicated that PdAu 3:1/C-1 was an alloy, whereas PdAu 3:1/C-2 was a heterogeneous mixture of the two metals. Moreover, transmission electron microscope analyses revealed that the PdAu 3:1/C-1 nanoparticles dispersed homogeneously on the carbon carrier without evident aggregation. Further, the X-ray photoelectron spectroscopy results demonstrated that the hydroxyl content was higher on the surface of PdAu 3:1/C-1 than that of PdAu 3:1/C-2. The increase of adsorptive hydroxyl on the surface of PdAu 3:1/C-1 could facilitate the adsorption and oxidation of CO on the catalyst surface, thus improving EOR activity and catalyst stability.