Simple preparation of Pd–Pt nanoalloy catalysts for methanol-tolerant oxygen reduction

Carbon-supported Pd–Pt bimetallic nanoparticles of different atomic ratios (Pd–Pt/C) have been prepared by a simple procedure involving the complexing of Pd and Pt species with sodium citrate followed by ethylene glycol reduction. As-prepared Pd–Pt alloy nanoparticles evidence a single-phase fcc disordered structure, and the degree of alloying is found to increase with Pd content. Both X-ray diffraction and transmission electron microscopy characterizations indicate that all the Pd–Pt/C catalysts possess a similar mean particle size of ca. 2.8 nm. The highest mass and specific activity of the oxygen reduction reaction (ORR) using the Pd–Pt/C catalysts are found with a Pd:Pt atomic ratio of 1:2. Moreover, all Pd–Pt alloy catalysts exhibit significantly enhanced methanol tolerance during the ORR than the Pt/C catalyst, ensuring a higher ORR performance while diminishing Pt utilization.