Facile Synthesis of Trimetallic Hexoctahedral Au@PdPt Nanoparticles for Electrocatalytic Oxidation of Methanol

In this study, trimetallic Au@PdPt nanoparticles (NPs) were synthesized by a seed-mediated technique, possessing a hexoctahedral (HOH) Au core with a branched PdPt alloy shell. The fabrication process involved the synthesis of HOH Au NPs exhibiting high-index {651} facet as nanotemplates, followed by the epitaxial growth of Pd and Pt on these NPs to yield HOH Au@PdPt NPs. The size and composition of HOH Au@PdPt NPs as well as the thickness of PdPt alloy shells (from 2 to 4, 5, and 8 nm) can be precisely adjusted by varying the quantity of Pd and Pt precursors. The catalytic efficacy of these Au@PdPt NPs was significantly enhanced through the synergistic effect between Au, Pd, and Pt, along with the increased contact areas afforded by multibranched PdPt alloy shells. For methanol electro-oxidation, the catalytic activity of HOH Au@PdPt NPs depends on the Pt content showing a distinctive volcano-type pattern. Remarkably, the HOH Au@Pd0.3Pt0.3 NPs demonstrate optimum catalytic performance for methanol oxidation in acidic conditions, exhibiting superior electrocatalytic properties compared to commercial Pt black catalysts. Their ECSA value, mass, and specific activities are 47.21 m2 g–1, 0.93 A mg–1, and 1.97 mA cm–2, respectively. This research can be exploited to fabricate catalysts possessing exceptional properties by precisely designing and controlling the size, composition and morphology of the trimetallic Au@PdPt NPs.