Facile synthesis of Pt–Pd bimetallic nanoparticles by plasma discharge in liquid and their electrocatalytic activity toward methanol oxidation in alkaline media

The Pt–Pd bimetallic nanoparticles for direct methanol fuel cell applications were successfully prepared by plasma discharge in aqueous solution. The obtained nanoparticles were characterized by energy dispersive X-ray spectroscopy, X-ray diffraction spectroscopy, and transmission electron microscopy. During plasma discharge, the nanoparticles were produced from the erosion of electrodes. It was noted that the erosion amount of anode electrodes was much greater than that of cathode electrodes so that the composition of Pt–Pd bimetallic nanoparticles could be changed with different power types and electrode configurations. Diffraction patterns fitted from Gaussian devolution indicated that the crystalline phase of Pt40Pd60 products was composed of pure Pt, pure Pd and Pt–Pd alloy phases. The morphology of synthesized nanoparticles showed that nanowires connected with quasi-spherical nanoparticles with 2–3 nm in diameter were observed and large spherical particles with > 50 nm in diameter were also detected intermittently. The cyclic voltammetric measurement and continuous potential scan demonstrated that Pt40Pd60 had much higher catalytic activity and better resistance to CO poisoning than Pt94Pd6 and Pt1Pd99 for methanol oxidation. These results indicate that the Pt40Pd60 could be an excellent candidate for the direct methanol fuel cell applications.