▎ 摘　　要

An advanced electrode for methanol oxidation in alkali medium, comprising Pd-Rh nanoparticles and reduced graphene oxide (r-GO) sheets, has been successfully synthesized by pulse microwave polyol (MP) technique. The MP technique is capable of depositing Pd-Rh nanoparticles on the surface of r-GO sheets under microwave irradiation. The atomic ratio of Pd:Rh is chosen as a crucial factor to examine the catalytic activity toward H adsorption/desorption and methanol oxidation. The Pd-Rh catalyst (with Pd:Rh ratio = 75:25) displays the highest alloying degree (similar to 41.5%), favoring the formation of Pd-Rh pairs in the binary crystals. On the Pd-Rh catalyst, the Pd site acts as major contributor toward hydrogen adsorption and methanol oxidation, whereas the neighboring Rh site serves as a promoting center to strip oxygenate species (e.g., Pd (CO)(ads) sites). The-enhanced catalytic activity on the Pd-Rh catalyst is attributed to the fact that the binary catalyst possesses a high alloying degree, leading to high catalytic coverage, high-level of CO tolerance, and superior cyclic durability. The Tafel slope of as-made Pd-Rh catalyst could reach as low as 63 mV dec(-1) among the electrodes, based on the analysis of Tafel plots. The Pd-Rh catalyst also exhibits both lower equivalent diffusion resistance and equivalent series resistance, as compared with pure Pd one. (C) 2015 Elsevier B.V. All rights reserved.