Assessment of Bulk Oxygen Capacity and Transient Redox Behavior of Foamed Lanthanum Strontium Manganese Perovskites

Journal Article · Wed Sep 27 00:00:00 UTC 2023 · Journal of Solar Energy Engineering

DOI: https://doi.org/10.1115/1.4063440 · OSTI ID:2522090

McCord, Dylan C. ^[1]; Gager, Elizabeth J. ^[2]; Lee, Kangjae ^[3]; McDaniel, Anthony H. ^[4]; Nino, Juan C. ^[2]; Scheffe, Jonathan R. ^[2]

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1. University of Florida, Gainesville, FL (United States); University of Florida
2. University of Florida, Gainesville, FL (United States)
3. DLR-German Aerospace Center, Cologne (Germany)
4. Sandia National Laboratories (SNL-CA), Livermore, CA (United States)

Synthesis of solar thermochemical hydrogen (STCH) production redox materials with engineered structures, for example, replica foams, can enable efficient heat and mass transport and are critical for scaled-up systems. Prior work has motivated the use of lanthanum strontium manganese (LSM)-type perovskites as foamed STCH materials, but the effect of their morphology on bulk and kinetic behavior has not been reported. In this work, replica and direct foamed samples of La_0.65Sr_0.35MnO_3-δ (LSM35) were fabricated and compared to synthesized powders and dense monoliths, and similarly synthesized CeO_2-δ (ceria) foams, regarding their specific reaction rates and bulk oxygen capacity/H₂ yields. Changes in oxygen capacity (Δδ) and reaction rates were measured between 1200 °C and 1400 °C by using fixed ratios of steam and hydrogen during both reduction and oxidation steps, allowing for analysis under practical high conversion conditions. Results suggest bulk behavior and reaction rates of the foamed LSM materials are comparable to their powder analogues. Differences in reaction rates were observed only when replica foamed samples were subjected to rapid laser heating (emulating conditions expected in solar furnaces), which is expected but has not been demonstrated at such a small scale. Here, foamed samples were further subjected to 50 redox cycles at 1400 °C to evaluate their stability. Results show no statistically significant decrease in hydrogen production for any of the foamed samples, but the direct foamed samples became brittle with time. Together, these results demonstrate the viability of replica foamed LSM perovskites for integration in scaled-up STCH systems.

• Research Organization: University of Florida, Gainesville, FL (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Office of Sustainable Transportation. Hydrogen Fuel Cell Technologies Office (HFTO)
• Grant/Contract Number: EE0008840; NA0003525
• OSTI ID: 2522090
• Journal Information: Journal of Solar Energy Engineering, Journal Name: Journal of Solar Energy Engineering Journal Issue: 2 Vol. 146; ISSN 0199-6231
• Publisher: ASMECopyright Statement
• Country of Publication: United States
• Language: English