Stabilization of Platinum Oxygen-Reduction Electrocatalysts Using Gold Clusters

Chemistry Department, Brookhaven National Laboratory, New York, New York, United States
Science (Impact Factor: 33.61). 02/2007; 315(5809):220-2. DOI: 10.1126/science.1134569
Source: PubMed


We demonstrated that platinum (Pt) oxygen-reduction fuel-cell electrocatalysts can be stabilized against dissolution under potential cycling regimes (a continuing problem in vehicle applications) by modifying Pt nanoparticles with gold (Au) clusters. This behavior was observed under the oxidizing conditions of the O2 reduction reaction and potential cycling between 0.6 and 1.1 volts in over 30,000 cycles. There were insignificant changes in the activity and surface area of Au-modified Pt over the course of cycling, in contrast to sizable losses observed with the pure Pt catalyst under the same conditions. In situ x-ray absorption near-edge spectroscopy and voltammetry data suggest that the Au clusters confer stability by raising the Pt oxidation potential.

29 Reads
  • Source
    • "The cathodic oxygen reduction reaction (ORR), O 2 + 4H + + 4e –   2H 2 O, is one of the most important electrochemical reactions due to its prominent role in renewable-energy technologies, such as fuel cells and metal–air batteries [1] [2] [3] [4] [5]. The electrocatalyst involved in the ORR plays a vital role in determining the performance of the energy devices, including power output, charge–discharge rate, energy efficiency, and cycling life [6] [7]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Cathodic oxygen reduction reaction (ORR) is a highly important electrochemical reaction in renewable-energy technologies. In general, the surface area, exposed facets and electrical conductivity of catalysts all play important roles in determining their electrocatalytic activities, while their performance durability can be improved by integration with supporting materials. In this work, we have developed a method to synthesize hybrid structures between PtPd bimetallic nanocages and graphene by employing selective epitaxial growth of single-crystal Pt shells on Pd nanocubes supported on reduced graphene oxide (rGO), followed by Pd etching. The hollow nature, {100} surface facets and bimetallic composition of PtPd nanocages, together with the good conductivity and stability of graphene, enable high electrocatalytic performance in ORR. The obtained PtPd nanocage–rGO structures exhibit mass activity (0.534 A·mg Pt −1 ) and specific activity (0.482 mA·cm−2) which are 4.4 times and 3.9 times greater than the corresponding values for Pt/C.
    Nano Research 09/2015; 8(9):2789-2799. DOI:10.1007/s12274-015-0770-6- · 7.01 Impact Factor
  • Source
    • "An effective electrocatalyst that can accelerate both the ORR and OER is crucial for the performance improvement of metal-air batteries. Platinum and its alloy, such as Pt/Au and Pt/Ir, have shown excellent bi-functional electrocatalytic activity for ORR and OER [8] [9] [10]. However, they suffer from the high price and low abundance. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The spinel-type MnCo2O4 is an attractive bifunctional electrocatalyst for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). However, the catalytic activity of MnCo2O4 is limited by its poor electronic conductivity. Herein MnCo2O4 coated with conducting polypyrrole (i.e. MCO@PPyhybrid) is synthesized. The obtained MCO@PPy hybrid exhibits excellent electrocatalytic activity for both the ORR and OER, outperforming pristine MCO, PPy and MCO+PPy mixture. The ORR and OER activities of MCO@PPy are comparable to that of the commercial Pt/C (20 wt.%) and RuO2/C (20 wt.%), benchmark electrocatalysts for ORR and OER, respectively. While the stabilities of MCO@PPy hybrid toward both the ORR and OER are much higher than that of Pt/C (20 wt.%) and RuO2/C (20 wt.%), respectively. The PPy coating on the surface of MCO provides a conductive network for fast electron transfer and the coupling between the PPy layer and MCO promotes the transfer of electrons from PPy to MCO, benefiting the ORR and OER. The results reveal the effectiveness of surface modification with conducting polymer on improving the electrocatalytic activity of spinel oxide.
    Electrochimica Acta 09/2015; 180:788. DOI:10.1016/j.electacta.2015.08.160 · 4.50 Impact Factor
    • "e l s e v i e r . c o m / l o c a t e / e l e c t a c t a oxidation potential [24] [25], therefore it could be expected that alloying platinum with gold would allow enhancing the durability of catalysts. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Carbon-supported monometallic, binary and ternary nanocatalysts based on Pt, Pd and Au were synthesized by a "water in oil" microemulsion method and characterized by atomic absorption spectrometry, thermogravimetry, transmission electron microscopy, X-ray diffraction, and electrochemical methods. A comparative study of the oxygen reduction reaction on monometallic, alloyed binary and ternary nanocatalysts has been performed. The catalytic activity and the selectivity of the nanocatalysts towards the ORR have been determined by rotating disc electrode and rotating ring disc electrode in O2-saturated 0.1 M HClO4 electrolyte. It was shown that the addition of palladium to platinum led to a constant decrease of the activity with the Pd ratio. The modification of platinum by gold allows improving the activity of the catalyst towards ORR for gold ratio up to 50 at%. Ternary Pt70Pd15Au15/C and Pt50Pd25Au25/C were synthesized. These catalysts showed improved catalytic activities towards ORR. Aging tests have been carried out, showing that a part of the loss in the activity of gold containing catalysts is due to gold segregation from the bulk to the surface of nanoparticles.
Show more

Similar Publications

Preview (2 Sources)

29 Reads
Available from