Ultrasonic-assisted synthesis of carbon nanotube supported bimetallic Pt-Ru nanoparticles for effective methanol oxidation

In this paper, we demonstrate a facile and one-step ultrasonic method to synthesize a carboxylate functionalized multi-walled carbon nanotube supported bimetallic platinum ruthenium nanoparticle (Pt-Ru/c-MWNT) catalyst. The results show that the atomic Pt-Ru ratio is approximately 1 : 1, and the Pt mass loading in the catalyst is 8%. In addition, Pt-Ru nanoparticles with bimetallic structure, ultrasmall size (1.9 nm), and uniform distribution were well-dispersed onto the surface of c-MWNTs, which exhibit enhanced electrocatalytic performance toward methanol oxidation. It is found that this catalyst has a much higher electrochemically active surface area (ECSA) (133.2 m(2) g(Pt)(-1)) and current density for methanol oxidation (1236.0 mA mg(Pt)(-1)) than those of commercial Pt/C (20 wt%) (55.6 m(2) g(Pt)(-1), 214.2 mA mg(Pt)(-1)). Furthermore, the oxidation current density of the Pt-Ru/c-MWNT catalyst at 10 000 s is 22.5 mA mg(Pt)(-1), which indicates a long-term high electrocatalytic activity of the Pt-Ru/c-MWNT catalyst for methanol oxidation in acid media.