Facile Synthesis\nof Trimetallic Hexoctahedral Au@PdPt\nNanoparticles for Electrocatalytic Oxidation of Methanol

In this study, trimetallic Au@PdPt\nnanoparticles (NPs)\nwere synthesized\nby a seed-mediated technique, possessing a hexoctahedral (HOH) Au\ncore with a branched PdPt alloy shell. The fabrication process involved\nthe synthesis of HOH Au NPs exhibiting high-index {651} facet as nanotemplates,\nfollowed by the epitaxial growth of Pd and Pt on these NPs to yield\nHOH Au@PdPt NPs. The size and composition of HOH Au@PdPt NPs as well\nas the thickness of PdPt alloy shells (from 2 to 4, 5, and 8 nm) can\nbe precisely adjusted by varying the quantity of Pd and Pt precursors.\nThe catalytic efficacy of these Au@PdPt NPs was significantly enhanced\nthrough the synergistic effect between Au, Pd, and Pt, along with\nthe increased contact areas afforded by multibranched PdPt alloy shells.\nFor methanol electro-oxidation, the catalytic activity of HOH Au@PdPt\nNPs depends on the Pt content showing a distinctive volcano-type pattern.\nRemarkably, the HOH Au@Pd<sub>0.3</sub>Pt<sub>0.3</sub> NPs demonstrate\noptimum catalytic performance for methanol oxidation in acidic conditions,\nexhibiting superior electrocatalytic properties compared to commercial\nPt black catalysts. Their ECSA value, mass, and specific activities\nare 47.21 m<sup>2</sup> g<sup>–1</sup>, 0.93 A mg<sup>–1</sup>, and 1.97 mA cm<sup>–2</sup>, respectively. This research\ncan be exploited to fabricate catalysts possessing exceptional properties\nby precisely designing and controlling the size, composition and morphology\nof the trimetallic Au@PdPt NPs.