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Abstract Sorption-enhanced steam reforming (SESR) of toluene (SESRT) using catalytic CO 2 sorbents is a promising route to convert the aromatic tar byproducts formed in lignocellulosic biomass gasification into hydrogen (H 2 ) or H 2 -rich syngas. Commonly used sorbents such as CaO are effective in capturing CO 2 initially but are prone to lose their sorption capacity over repeated cycles due to sintering at high temperatures. Herein, we present a demonstration of SESRT using A- and B-site doped Sr 1− x A’ x Fe 1− y B’ y O 3− δ (A’ = Ba, Ca; B’ = Co) perovskites in a chemical looping scheme. We found that surface impregnation of 5–10 mol% Ni on the perovskite was effective in improving toluene conversion. However, upon cycling, the impregnated Ni tends to migrate into the bulk and lose activity. This prompted the adoption of a dual bed configuration using a pre-bed of NiO/ γ –Al 2 O 3 catalyst upstream of the sorbent. A comparison is made between isothermal operation and a more traditional temperature-swing mode, where for the latter, an average sorption capacity of ∼38% was witnessed over five SESR cycles with H 2 -rich product syngas evidenced by a ratio of H 2 : CO x > 4.0. XRD analysis of fresh and cycled samples of Sr 0.25 Ba 0.75 Fe 0.375 Co 0.625 O 3- δ reveal that this material is an effective phase transition sorbent—capable of cyclically capturing and releasing CO 2 without irreversible phase changes occurring.
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Ruddlesden–Popper Structured Sr 3 Fe 2 O 7−δ as Redox‐Activated CO 2 Sorbents for Green Hydrogen Production
Conventional methods for hydrogen production, such as steam methane reforming, face increasing scrutiny due to their reliance on fossil fuels, high CO2emissions, and significant capital costs. Sorption‐enhanced steam reforming using renewable feedstocks, where CO2is captured in situ, presents a more sustainable alternative. This study investigates the suitability of A‐ and B‐site doped strontium ferrite‐type Ruddlesden–Popper oxides (RPO) as robust CO2sorbents, with particular attention on their application in glycerol‐based hydrogen production. Packed bed reactor experiments, complemented by comprehensive characterizations, are systematically conducted to assess and compare the performance of RPO with a stoichiometry of (SrxCa1−x)2Fe0.9Ni0.1O4−δ(RPOs) with that of traditional perovskite oxides, that is, SrxCa1−xFe0.9Ni0.1O4−δ(POs), and to unravel the underlying phase transition pathways. Specifically, RPO with a nominal stoichiometry of Sr1.4Ca0.6Fe0.9Ni0.1O4−δforms an Sr3Fe2O7‐type active phase, exhibiting high H2purities (≈95 vol%) coupled with stable CO2sorption capacity. Notably, its CO2prebreakthrough time is more than six times longer than that of its perovskite counterpart in the sequential Ni‐bed configuration. Finally, the interplay between the reduction and carbonation reactions is examined, highlighting the synergistic benefits that enable the sorbent to fully realize its CO2uptake potential.
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- Award ID(s):
- 1923468
- PAR ID:
- 10679167
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Advanced Energy and Sustainability Research
- Volume:
- 7
- Issue:
- 1
- ISSN:
- 2699-9412
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1002/aesr.202500213
