Sub-Nanometer-Resolution Elemental Mapping of "Pt3Co" Nanoparticle Catalyst Degradation in Proton-Exchange Membrane Fuel Cells

被引：69

作者：

Carlton, Christopher E. ^{[1
,2
]}

Chen, Shuo ^{[1
,2
]}

Ferreira, Paulo J. ^{[3
]}

Allard, Lawrence F. ^{[4
]}

Shao-Horn, Yang ^{[1
,2
]}

机构：

[1] MIT, Dept Mech Engn, Cambridge, MA 02139 USA

[2] MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA

[3] Univ Texas Austin, Mat Sci & Engn Program, Austin, TX 78712 USA

[4] Oak Ridge Natl Lab, Mat Sci & Technol Div, Oak Ridge, TN 37831 USA

来源：

JOURNAL OF PHYSICAL CHEMISTRY LETTERS | 2012年 / 3卷 / 02期

基金：

美国国家科学基金会;

关键词：

OXYGEN REDUCTION REACTION; PLATINUM MONOLAYER; PT-CO; ALLOYS; ELECTROCATALYSTS; SURFACES; ENHANCEMENT; INSTABILITY; STABILITY; MECHANISM;

D O I：

10.1021/jz2016022

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The efficiency of proton exchange membrane fuel cells (PEMFCs) is limited largely by sluggish oxygen reduction reaction (ORR) kinetics, even when promoted by Pt-based alloy nanoparticles (NPs). Acid-leached Pt alloys such as "Pt3Co" have shown considerably higher specific (2-5 times) and mass (2 to 3 times) ORR activity than Pt NPs. However, the specific activity enhancement of "Pt3Co" NPs decreases during PEMFC operation, which has been attributed to the formation of a Pt-enriched shell near the NP surfaces. In this study, we report direct evidence of surface Pt and Co compositional changes in acid-treated "Pt3Co" NPs after PEMFC voltage cycling using energy-dispersive spectroscopy mapping in an aberration-corrected scanning transmission electron microscope with subnanometer resolution. Acid-treated "Pt3Co" NPs were found to have Pt-enriched shells of similar to 0.5 nm, whereas the Pt-enriched-shell became thicker (similar to 1-6 nm) after PEMFC voltage cycling, where greater shell thicknesses were associated with larger "Pt3Co" NPs.

引用

页码：161 / 166

页数：6

共 37 条

[1] Platinum monolayer fuel cell electrocatalysts [J].

Adzic, R. R. ;

Zhang, J. ;

Sasaki, K. ;

Vukmirovic, M. B. ;

Shao, M. ;

Wang, J. X. ;

Nilekar, A. U. ;

Mavrikakis, M. ;

Valerio, J. A. ;

Uribe, F. .

TOPICS IN CATALYSIS, 2007, 46 (3-4) :249-262

[2]

Ball S.C., 2007, ECS T, V11, P1267

[3] Enhanced activity for oxygen reduction reaction on "Pt3CO" nanoparticles:: Direct evidence of percolated and sandwich-segregation structures [J].

Chen, Shuo ;

Ferreira, Paulo J. ;

Sheng, Wenchao ;

Yabuuchi, Naoaki ;

Allard, Lawrence F. ;

Shao-Horn, Yang .

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2008, 130 (42) :13818-13819

[4] Platinum-Alloy Cathode Catalyst Degradation in Proton Exchange Membrane Fuel Cells: Nanometer-Scale Compositional and Morphological Changes [J].

Chen, Shuo ;

Gasteiger, Hubert A. ;

Hayakawa, Katsuichiro ;

Tada, Tomoyuki ;

Shao-Horn, Yang .

JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 2010, 157 (01) :A82-A97

[5] Origin of Oxygen Reduction Reaction Activity on "Pt3Co" Nanoparticles: Atomically Resolved Chemical Compositions and Structures [J].

Chen, Shuo ;

Sheng, Wenchao ;

Yabuuchi, Naoaki ;

Ferreira, Paulo J. ;

Allard, Lawrence F. ;

Shao-Horn, Yang .

JOURNAL OF PHYSICAL CHEMISTRY C, 2009, 113 (03) :1109-1125

[6] QUANTITATIVE-ANALYSIS OF THIN SPECIMENS [J].

CLIFF, G ;

LORIMER, GW .

JOURNAL OF MICROSCOPY-OXFORD, 1975, 103 (MAR) :203-207

[7] Further insights into the durability of Pt3Co/C electrocatalysts: Formation of "hollow" Pt nanoparticles induced by the Kirkendall effect [J].

Dubau, L. ;

Durst, J. ;

Maillard, F. ;

Guetaz, L. ;

Chatenet, M. ;

Andre, J. ;

Rossinot, E. .

ELECTROCHIMICA ACTA, 2011, 56 (28) :10658-10667

[8] An atomistic description of dealloying - Porosity evolution, the critical potential, and rate-limiting behavior [J].

Erlebacher, J .

JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 2004, 151 (10) :C614-C626

[9] Evolution of nanoporosity in dealloying [J].

Erlebacher, J ;

Aziz, MJ ;

Karma, A ;

Dimitrov, N ;

Sieradzki, K .

NATURE, 2001, 410 (6827) :450-453

[10] Formation mechanism of Pt single-crystal nanoparticles in proton exchange membrane fuel cells [J].

Ferreira, P. J. ;

Shao-Horn, Yang .

ELECTROCHEMICAL AND SOLID STATE LETTERS, 2007, 10 (03) :B60-B63

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