Pt-Guided Formation of Pt-Ag Alloy Nanoislands on Au Nanorods and Improved Methanol Electro-Oxidation

A simple and facile method was developed to fabricate alloyed Pt−Ag nanoislands on Au nanorods (denoted as Au@Pt−Ag NRs). The island growth mode of Pt on the Au rod was employed to guide the growth behavior of Pt−Ag alloys. The formation of the Pt−Ag alloy was confirmed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), XRD (X-ray diffraction), XPS (X-ray photoelectron spectroscopy), UV−visible absorption spectra, and electrochemical characterization. The alloy compositions can be tuned within the broad miscibility gap from Ag9Pt91 to Ag83Pt17 by controlling the ratios of PtCl42−/Ag+. The Au@Pt−Ag NRs show tunable surface plasmon resonance (SPR) and enhanced catalytic activity for methanol electro-oxidation, pointing to a potential future of nanometerized Pt−Ag alloys in fuel cells and other related fields. Apart from Pt−Ag, this strategy may be applied to the formation of Pt-related bimetallic (trimetallic) systems.