Nano-structured platinum group metal-free catalysts and their integration in fuel cell electrode architectures

Journal Article · Sat Aug 26 00:00:00 EDT 2017 · Applied Catalysis B: Environmental

DOI:https://doi.org/10.1016/j.apcatb.2017.08.067· OSTI ID:1493739

Serov, Alexey ^[1]; Shum, Andrew D. ^[2]; Xiao, Xianghui ^[3]; De Andrade, Vincent ^[3]; Artyushkova, Kateryna ^[1]; Zenyuk, Iryna V. ^[2]; Atanassov, Plamen ^[1]

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1. Univ. of New Mexico, Albuquerque, NM (United States)
2. Tufts Univ., Medford, MA (United States)
3. Argonne National Lab. (ANL), Argonne, IL (United States)

The novel platinum group metal-free (PGM-free) catalyst for the oxygen reduction reaction (ORR) is synthesized by a modified sacrificial support method (SSM). The catalyst chemical/surface composition is studied by X-ray photoelectron spectroscopy, and the morphology of the material is observed using both HR-SEM and HR-TEM, demonstratingthe open-frame, self-supported catalysts. This new catalyst’s electrochemical performance is evaluated by polarization curves and has behaviour comparable to the state-of-the-art PGM-free catalysts. Meso-structure imaging shows pores on the order of 100 nm, the mean size of the individual silica particles in the sacrificial support. For the first time, PGM-free catalyst layer (CL) morphology in a membrane electrode assembly (MEA) is studied in detail by combined nano- and micro X-ray computed tomography (CT) and interpretational modelling. The highly inhomogeneous, high-tortuosity, through-thickness structure of the CL is observed with micro-CT. The nano-CT method for these thick PGM-free electrodes is not sufficient to capture the full through-thickness morphology of these electrodes. Water retention curves suggest water pooling at the MEA components‘ interfaces and significant dependence of capilary pressure and saturation on through-thickness location. Lastly, this study is the first of its kind to identify morphology-dependent transport losses in the thick PGM-free electrodes using scale-bridging between meso-, micro-, and macro.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 1493739
• Alternate ID(s): OSTI ID: 1693864
• Journal Information: Applied Catalysis B: Environmental, Vol. 237, Issue C; ISSN 0926-3373
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
fuel-cells
platinum group metal-free catalysts
water management
x-ray computed tomography