Article

Stabilization of Platinum Oxygen-Reduction Electrocatalysts Using Gold Clusters.

Chemistry Department, Brookhaven National Laboratory, New York, New York, United States
Science (Impact Factor: 31.48). 02/2007; 315(5809):220-2. DOI: 10.1126/science.1134569
Source: PubMed

ABSTRACT 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.

2 Followers
 · 
150 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Hierarchically porous N-doped carbon nanoflakes (HPNCNFs) were facilely synthesized on a large scale via pyrolysis of 1,8-diaminonaphthalene (DAN)/FeCl3·6H2O mixture under Ar followed by acid leaching. Both pyrolysis temperature and the amount of Fe species have strong influence on catalyst activity. It suggests that the presence of large excess Fe species not only is key to nanoflake formation but also serves as a mesopore-forming agent. The HPNCNF-900 catalyst, obtained at 900 °C with a mass ratio 1:5 of DAN to FeCl3·6H2O, was found to exhibit superhigh oxygen reduction reaction activity and excellent durability in alkaline media outperforming the state-of-the-art Pt/C catalyst at a moderate loading.
    Carbon 11/2014; 78:60–69. DOI:10.1016/j.carbon.2014.06.048 · 6.16 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Graphene nanosheet (GNS) has a remarkably high ratio of surface area to thickness and intense inter-sheet aggregation, which heavily resist mass diffusion in vertical orientation. Here, we establish a fast-speed mass diffusion passage by creating pores in GNS, and the corresponding Pt catalyst (Pt/rPGO) displays 15.5 times mass diffusion rate than that of the pristine GNS supported Pt catalyst (Pt/rGO). Thus, the Pt/rPGO catalyst Exhibits 1.5 times increase in Pt mass activity toward oxygen reduction reaction compared with the Pt/rGO. Significantly, after H2 thermal treatment, the mass activity of the Pt/rPGO further increases to 1.9 times that of the Pt/rGO, and its electrochemical stability is also greatly improved.
    Electrochimica Acta 06/2014; 132:356–363. DOI:10.1016/j.electacta.2014.03.181 · 4.09 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: FePt nanoparticles (NPs)/reduced graphene oxide (rG-O) composites have been synthesized using a one-pot strategy without surfactants. Monodisperse FePt NPs were homogenously loaded onto rG-O sheets. By controlling the concentration of dispersed graphene oxide (GO), uniform FePt flower-like nanoclusters can be obtained. FePt/rG-O composites exhibited exceptionally high electrocatalytic performance in the activity and durability for the oxygen reduction reaction (ORR), much superior to that of the commercial Pt/C (60%). The straightforward synthesis of FePt/rG-O composites provides a low-cost and high performance catalyst for the ORR, which is also a promising strategy for the synthesis of various Pt-based bimetallic alloy/rG-O composites for potential uses in catalysis and energy fields.
    Carbon 05/2014; 68:755. · 6.16 Impact Factor

Preview

Download
8 Downloads
Available from