Abstract

Proton exchange membrane fuel cells (PEMFCs) are a promising zero-emission power source for heavy-duty vehicles (HDVs). However, long-term durability of up to 25,000 h is challenging because current carbon support, catalyst, membrane, and ionomer developed for traditional light-duty vehicles cannot meet the stringent requirement. Therefore, understanding catalyst degradation mechanisms under the HDV condition is crucial for rationally designing highly active and durable platinum group metal (PGM) catalysts for high-performance membrane electrode assemblies (MEAs). Herein, we report a PGM catalyst consisting of platinum nanoparticles with a high content (40 wt %) on atomic-metal-site (e.g., MnN₄)-rich carbon support. MEAs with the Pt (40 wt %)/Mn–N–C cathode catalyst achieved significantly enhanced performance and durability, generating 1.41 A cm^–2 at 0.7 V under HDV conditions (0.25 mgPt cm^–2 and 250 kPa_abs pressure) and retaining 1.20 A cm^–2 after an extended and accelerated stress test up to 150,000 voltage cycles. Electron microscopy studies indicate that most fine Pt nanoparticles are retained on or/and in the carbon support covered with the ionomer throughout the catalyst layer at the end of life. During the long-term stability test, the observed electrochemical active surface area reduction and performance loss primarily result from Pt depletion in the catalyst layer duemore » to Pt dissolution and redeposition at the interface of the cathode and membrane. Importantly, the first-principle density functional theory calculations further reveal a support entrapment effect of the Mn–N–C, in which the MnN₄ site can specifically adsorb the Pt atom and further retard the Pt dissolution and migration, therefore enhancing long-term MEA durability.« less

Authors:

Zeng, Yachao ^[1]; Liang, Jiashun ^[1]; Li, Boyang ^[2]; Yu, Haoran  ^[3];

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• Search DOE PAGES for ORCID "0000-0001-7304-2840"

Zhang, Bingzhang ^[1]; Reeves, Kimberly Shawn ^[3]; Cullen, David A.  ^[3];

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• Search DOE PAGES for ORCID "0000-0002-2593-7866"

Li, Xing  ^[4];

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• Search DOE PAGES for ORCID "0000-0002-4524-600X"

Su, Dong  ^[5];

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• Search DOE PAGES for ORCID "0000-0002-1921-6683"

Wang, Guofeng  ^[2];

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• Search DOE PAGES for ORCID "0000-0001-8249-4101"

Zhong, Sichen  ^[6];

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• Search DOE PAGES for ORCID "0000-0002-8486-9277"

Xu, Hui ^[6]; Macauley, Natalia ^[6]; Wu, Gang  ^[1]

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• Search DOE PAGES for ORCID "0000-0003-0885-6172"

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+ Show Author Affiliations

1. State Univ. of New York at Buffalo, NY (United States)
2. Univ. of Pittsburgh, PA (United States)
3. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
4. Zhengzhou University (China). Key Laboratory of Materials Physics of Ministry of Education
5. Chinese Academy of Sciences (CAS), Beijing (China). Beijing National Laboratory for Condensed Matter Physics
6. Giner Inc., Newton, MA (United States)

Publication Date:

Thu Aug 24 00:00:00 EDT 2023

Research Org.:

Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE), Office of Sustainable Transportation. Hydrogen Fuel Cell Technologies Office (HFTO); USDOE Office of Nuclear Energy (NE), Nuclear Fuel Cycle and Supply Chain. Fuel Cycle Research and Development Program; USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)

OSTI Identifier:

2224159

Grant/Contract Number:  

AC05-00OR22725; SC0021671

Resource Type:

Accepted Manuscript

Journal Name:

ACS Catalysis

Additional Journal Information:

Journal Volume: 13; Journal Issue: 18; Journal ID: ISSN 2155-5435

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; electrocatalysis; oxygen reduction; single metal sites; carbon support; PGM catalysts