(Invited) Kinetic Models for the Degradation Mechanisms of PGM-Free ORR Catalysts

Journal Article · Tue Jun 19 00:00:00 EDT 2018 · ECS Transactions (Online)

DOI:https://doi.org/10.1149/08513.1239ecst· OSTI ID:1471365

Yin, Xi  ^[1]; Zelenay, Piotr  ^[1]

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1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Platinum group metal-free (PGM-free) catalysts, based on earth-abundant elements such as carbon, nitrogen, and transition metals, have shown promising oxygen reduction reaction (ORR) activity in fuel cells. Intensive research activities have focused on the improvement of activity and understanding of active sites in PGM-free catalysts. However, the durability of PGM-free catalysts in fuel cell cathode under realistic operating conditions has been addressed to a much lesser degree than the initial ORR activity, with only qualitative degradation mechanisms proposed to account for the generally fast activity loss in the fuel cell. Herein, we introduce to PGM-free ORR electrocatalysis a quantitative logistic decay model, based on a two-step autocatalytic degradation mechanism to portray catalyst degradation behavior. This model describes well the current-time data measured in the kinetic range of the fuel cell (fuel cell cathode) operation. Here, the results further suggest that the formation of deactivation species during the ORR is responsible for the loss of catalytic active sites and ensuing cell performance loss.

• Research Organization: Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Sustainable Transportation Office. Hydrogen Fuel Cell Technologies Office
• Grant/Contract Number: AC52-06NA25396
• OSTI ID: 1471365
• Report Number(s): LA-UR-18-24640
• Journal Information: ECS Transactions (Online), Vol. 85, Issue 13; ISSN 1938-6737
• Publisher: Electrochemical Society
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
PGM-free ORR Catalyst
non-PGM ORR Catalyst
Oxygen reduction reaction
Fe-C-N catalyst
Durability
Fuel cell
Kinetic models
Logistic decay
Exponential decay
Double exponential decay