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junkpengli

铜虫 (小有名气)

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虫号: 1098995
注册: 2010-09-14
性别: MM
专业: 凝聚态物性I:结构、力学和

[交流] Nature Materials和Nano Lett最新关于PEM fuel cell ORR的intermetallic催化剂的文章

Structurally ordered intermetallic platinum–cobalt core–shell nanoparticles with enhanced activity and stability as oxygen reduction electrocatalysts
Deli Wang*, Huolin L. Xin*, Robert Hovden, Hongsen Wang, Yingchao Yu, David A. Muller, Francis J. DiSalvo & Héctor D. Abruña
Published online: 28 October 2012 | doi:10.1038/nmat3458
Enhancing and optimizing the performance and durability of nanocatalysts for the oxygen reduction reaction is crucial for fuel-cell applications. A class of Pt–Co nanocatalysts consisting of ordered Pt3Co intermetallic cores with a 2–3 atomic-layer-thick platinum shell now exhibit a large increase in mass activity and specific activity when compared with disordered alloy nanoparticles.

Tuning Oxygen Reduction Reaction Activity via Controllable Dealloying: A Model Study of Ordered Cu3Pt/C Intermetallic Nanocatalysts
http://pubs.acs.org/doi/abs/10.1021/nl302404g
A promising electrocatalyst prototype of low Pt mole fraction, intermetallic nanoparticles of Cu3Pt, has been prepared using a simple impregnation-reduction method, followed by a post heat-treatment. Two dealloying methods (electrochemical and chemical) were implemented to control the atomic-level morphology and improve performance for the oxygen reduction reaction (ORR). The morphology and elemental composition of the dealloyed nanoparticles were characterized at angstrom resolution using an aberration-corrected scanning transmission electron microscope equipped with an electron energy loss spectrometer. We found that the electrochemical dealloying method led to the formation of a thin Pt skin of ca. 1 nm in thickness with an ordered Cu3Pt core structure, while chemical leaching gave rise to a “spongy” structure with no ordered structure being preserved. A three-dimensional tomographic reconstruction indicated that numerous voids were formed in the chemically dealloyed nanoparticles. Both dealloying methods yielded enhanced specific and mass activities toward the ORR and higher stability relative to Pt/C. The spongy nanoparticles exhibited better mass activity with a slightly lower specific activity than the electrochemically dealloyed nanoparticles after 50 potential cycles. In both cases, the mass activity was still enhanced after 5000 potential cycles.

另附几篇重要的JACS, Nano Letters相关的文章

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