Graphene-supported Pd–Ru nanoparticles with superior methanol electrooxidation activity Original Research Article

Pd–Ru bimetallic nanoparticles dispersed on graphene nanosheets (GNS) have been obtained by a microwave-assisted polyol reduction method and investigated for methanol electrooxidation in 1 M KOH + 1 M CH3OH at 25 °C. Structural and electrochemical characterizations of electrocatalysts are carried out by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, cyclic voltammetry, CO stripping voltammetry and chronoamperometry. The study shows that introduction of Ru (1–10 wt.%) into 40 wt.%Pd/GNS produces an alloy of Pd and Ru with the face centered cubic crystal structure. The electrocatalytic activity increased with increasing percentage of Ru in the Pd–Ru alloy showing maximum with 5 wt.%Ru. The electrocatalytic activity of the 40 wt.%Pd–5 wt.%Ru/GNS electrode at E = −0.10 V vs. Hg/HgO was ∼2.6 times greater than that of the base (40 wt.%Pd/GNS) electrode. Based on the methanol oxidation current, measured at 1 h during the chronoamperometry tests at E = −0.10 V vs. Hg/HgO, the active 40 wt.%Pd–5 wt.%Ru/GNS electrode exhibited ∼72% and ∼675% higher poisoning tolerance as compared to 40%Pd/GNS and 40%Pd/multiwalled carbon nanotube electrodes, respectively.