Self-Supported Interconnected Pt Nanoassemblies as Highly Stable Electrocatalysts for Low-Temperature Fuel Cells

School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457, Singapore.
Angewandte Chemie International Edition (Impact Factor: 11.26). 07/2012; 51(29):7213-6. DOI: 10.1002/anie.201201553
Source: PubMed


In it for the long haul: Clusters of Pt nanowires (3D Pt nanoassemblies, Pt NA) serve as an electrocatalyst for low-temperature fuel cells. These Pt nanoassemblies exhibit remarkably high stability following thousands of voltage cycles and good catalytic activity, when compared with a commercial Pt catalyst and 20 % wt Pt catalyst supported on carbon black (20 % Pt/CB).

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    • "Meantime, all the patterns clearly showed other three main characteristic peaks of face-centered cubic crystalline within 30–80°. For Pd/CNTs and Pt/CNTs, three peaks were observed, which matched well with those of Pd (01-1201) [37] and Pt (04-0802) [38] respectively in the Joint Committee Powder Diffraction Standard. It was noteworthy that the 2h values of the (1 1 1) lattice plane [39] for the Pd 3 Pt/CNTs, PdPt/CNTs and Fig. 1. "
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    ABSTRACT: Herein, a facile ultrasonic-assisted strategy was proposed to fabricate the Pd-Pt alloy/multi-walled carbon nanotubes (Pd-Pt/CNTs) nanocomposites. A good number of Pd-Pt alloy nanoparticles with an average of 3.4 ± 0.5 nm were supported on sidewalls of CNTs with uniform distribution. The composition of the Pd-Pt/CNTs nanocomposites could also be easily controlled, which provided a possible approach for the preparation of other architectures with anticipated properties. The Pd-Pt/CNTs nanocomposites were extensively studied by electron microscopy, induced coupled plasma atomic emission spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, and applied for the ethanol and methanol electro-oxidation reaction in alkaline medium. The electrochemical results indicated that the nanocomposites had better electrocatalytic activities and stabilities, showing promising applications for fuel cells.
    Ultrasonics Sonochemistry 07/2015; 28. DOI:10.1016/j.ultsonch.2015.07.021 · 4.32 Impact Factor
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    • "These intrinsic features render them emerging candidates for high–performance advanced nanomaterials in a wide variety of fields, wherein those for nanocatalysts have gained particular attention5610111617181920212223. Tremendous efforts have been devoted to branched NMNCs5610111617181920212223. Most of the works focus on Pt, Pd, and bimetallic species, etc.561011121314151617181920212223, the paradigms concerning Au are relatively few1624, although there has currently been an increasing interest in Au nanoarchitectures due to their promising surface–sensitive uses325262728. "
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    ABSTRACT: Well-defined noble metal nanocrystals (NMNCs) of a unique morphology yet a uniform facet have attracted broad interests. In this regard, those with a highly branched architecture have gained particular attention. Most of the currently existing branched NMNCs, however, are enclosed by mixed facets. We now report that branched Au nanoarchitectures could be facilely fabricated by mixing an aqueous solution of KAuCl4, an aqueous dispersion of graphene oxide, and ethanol under ambient conditions. Interestingly, unilike the conventional branched NMNCs, our unique Au nanostructures are predominately enriched with a uniform facet of {111}. Compared to the spherical Au nanostructures exposed with mixed facets, our branched nanospecies of a uniform facet display superior catalytic performances both for the catalytic reduction of 4-nitrophenol and the electrocatalytic oxidation of methanol. Our investigation represents the first example that Au nanostructures simultaneously featured with a highly branched architecture and a uniform crystal facet could be formulated. Our unique Au nanostructures provide a fundamental yet new scientific forum to disclose the correlation between the surface atomic arrangement and the catalytic performances of branched NMNCs.
    Scientific Reports 06/2014; 4:5259. DOI:10.1038/srep05259 · 5.58 Impact Factor
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    • "Detailed synthetic procedures are described in the Methods section. Transmission electron microscopy (TEM) characterization (Figures 1a and b) showed that Pt3Co NPs were well-dispersed on the KB particles utilizing the steric repulsion of CTAB tails (Supplementary Fig. S1 for the case without a CTAB treatment)3334. A fast Fourier transformed (FFT) pattern obtained for two Pt3Co NPs (Figure 1b inset) exhibited the spots corresponding to the (1-11), (200), and (11-1) planes of Pt3Co under the face-centered cubic (fcc) crystal structure, thus confirming the valid crystal structure of the synthesized NPs35. Also, the scanning transmission electron microscopy (STEM) image of the Pt3Co/KB composite and its corresponding energy-dispersive X-ray spectroscopy (EDAX) elemental mapping (Figure 1c) verify the uniformly distributed Pt3Co NPs. "
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    ABSTRACT: Most Li-O2 batteries suffer from sluggish kinetics during oxygen evolution reactions (OERs). To overcome this drawback, we take the lesson from other catalysis researches that showed improved catalytic activities by employing metal alloy catalysts. Such research effort has led us to find Pt3Co nanoparticles as an effective OER catalyst in Li-O2 batteries. The superior catalytic activity was reflected in the substantially decreased overpotentials and improved cycling/rate performance compared to those of other catalysts. Density functional theory calculations suggested that the low OER overpotentials are associated with the reduced adsorption strength of LiO2 on the outermost Pt catalytic sites. Also, the alloy catalyst generates amorphous Li2O2 conformally coated around the catalyst and thus facilitates easier decomposition and higher reversibility. This investigation conveys an important message that understanding elementary reactions and surface charge engineering of air-catalysts are one of the most effective approaches in resolving the chronic sluggish charging kinetics in Li-O2 batteries.
    Scientific Reports 02/2014; 4:4225. DOI:10.1038/srep04225 · 5.58 Impact Factor
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