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Tuning Oxygen Reduction Reaction Activity via Controllable Dealloying: A Model Study of Ordered Cu3Pt/C Intermetallic Nanocatalysts
被引:296
作者:
Wang, Deli
[1
]
Yu, Yingchao
[1
]
Xin, Huolin L.
[2
]
Hovden, Robert
[5
]
Ercius, Peter
[3
]
Mundy, Julia A.
[5
]
Chen, Hao
[1
]
Richard, Jonah H.
[4
]
Muller, David A.
[5
,6
]
DiSalvo, Francis J.
[1
]
Abruna, Hector D.
[1
]
机构:
[1] Cornell Univ, Dept Chem & Chem Biol, Ithaca, NY 14853 USA
[2] Cornell Univ, Dept Phys, Ithaca, NY 14853 USA
[3] Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Natl Ctr Electron Microscopy, Berkeley, CA 94720 USA
[4] Bard Coll, Dept Phys, Annandale On Hudson, NY 12504 USA
[5] Cornell Univ, Sch Appl & Engn Phys, Ithaca, NY 14853 USA
[6] Cornell Univ, Kavli Inst, Ithaca, NY 14853 USA
基金:
美国国家科学基金会;
关键词:
Fuel cell;
ORR;
electrocatalyst;
ordered intermetallic nanoparticle;
dealloying;
PT-M M;
ELECTROCATALYTIC ACTIVITY;
CO;
CATALYSTS;
NANOPARTICLES;
NI;
MICROSCOPY;
STABILITY;
SURFACES;
ALLOYS;
D O I:
10.1021/nl302404g
中图分类号:
O6 [化学];
学科分类号:
0703 ;
摘要:
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.
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页码:5230 / 5238
页数:9
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