Rational syntheses of core-shell Fe@(PtRu) nanoparticle electrocatalysts for the methanol oxidation reaction with complete suppression of CO-poisoning and highly enhanced activity

We report the syntheses of ternary nanoparticles (NPs) of Fe-x@(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 the 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 coupled 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 compared to a 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 CO-poisoning. Chronoamperometry data for MOR on the ternary NPs show improved stability over Pt/C and PtRu references.