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

Abstract

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 PtCl4 2−/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.

Porous platinum mesoflowers with enhanced activity for methanol oxidation reaction

“…It appears that although the remained Ag produces a negative effect on anodic scanning current density, the Pt-Ag alloys presents a better CO tolerance than pure Pt catalyst. This result was also proved by He and Peng in their recent works [20,43].…”

Activation/Inhibition Effects during the Coelectrodeposition of PtAg Nanoparticles: Application for ORR in Alkaline Media

“…However, there are reports which claim alloy formation between Ag and Pt even within the miscibilty gap. [4,6,9,10] On the other hand, the preferential deposition of the less noble metal, a so-called anomalous codeposition, has been shown previously for, for example, ZnNi, FeNi, FeCo, and CoNi. [24][25][26][27][28] Here, the less noble metal inhibits the deposition of the more noble one, whereas the more noble metal enhances the deposition of the less noble one.…”

“…For the oxidation of methanol and formic acid even higher activities were reported with PtAg than with Pt. [4][5][6] Thus, PtAg bimetallic nanoparticles are an interesting catalytic system to be studied.…”

Controlled synthesis and multifunctional properties of FePt-Au heterostructures

“…We observed an even more enhanced activity over FePt when it was combined with Au. It is known that Au can improve Pt catalyst activity by reducing CO poisoning effects [58][59][60]. The enhanced catalytic activity we observed for the FePt NRs is probably due to the enhanced tolerance of the hybrid catalyst to CO poisoning.…”