We report the syntheses of ternary nanoparticles (NPs) of Fex@(PtRu)(1-x)/2 (x = 0.0, 0.30, 0.34, 0.38, and 0.44) with Fe cores and PtRu alloy shells, which exhibit greatly improved electrocatalytic properties for methanol oxidation reaction (MOR). The syntheses were achieved by one-step sonochemical treatments of Pt(acac)2, Ru(acac)3, and Fe(acac)3 in ethylene glycol. The NPs are characterized by X-ray diffractometry, transmission electron microscopy (TEM), and inductively couple plasma-adsorption emission spectroscopy for the particle size, morphology, and composition, respectively. The formation of core-shell NPs has been proven by scanning TEM-energy dispersive X-ray spectroscopy, and the electronic structures of the elements have been investigated by X-ray photoelectron spectroscopy and X-ray adsorption near edge spectroscopy. The ternary NPs show enhanced MOR electrocatalytic activity from that of commercial PtRu-alloy (PtRu) by a factor of up to 2.5 based on the forward current density data. More importantly, the ternary NPs show complete suppression of COpoisoning. Chronoamperometry data for MOR on the ternary NPs show improved stability over Pt/C and PtRu references.

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We report on the syntheses of core-shell Fex@Pt (x = 0.4–1.2) nanoparticles (NPs) with Pt-shell thickness systematically controlled while the overall particle size is constant. The syntheses were achieved via one-pot ultrasound-assisted polyol synthesis (UPS) reactions. Fe1.2@Pt showed a record-breaking high core-element content (55 at%) of core-shell NPs. Based on observations from a series of control experiments, we propose a mechanism of the NPs' formation that enables control of shell thickness in UPS reactions. Fex@Pt NPs showed drastic enhancements in mass and specific activity for oxygen reduction reaction (ORR) and significantly enhanced durability compared to commercial Pt NPs. Fex@Pt with a 1 (monolayer) ML Pt shell showed the highest activity. The ab initio density functional theory calculations on the binding energies of oxygen species on the surfaces of Fex@Pt NPs showed that the 1 ML case is most favourable for the ORR, and in good agreement with the experimental results.