Phase segregation-dictated superior Fe-rich ferrite composite for intensified methane dry reforming with CO2 splitting
Loading...
Date
2025-03-01
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
Earth-abundant iron oxide serves as a promising oxygen carrier for the chemical looping dry reforming of methane, addressing the emission of both CH4 and CO2. However, its development faces a challenge with a trade-off between high activity and stability. We successfully resolved this issue by advancing an Fe-rich (61 wt% Fe) oxygen carrier derived from a global waste, fly ash. This oxygen carrier incorporates six cations (Fe, Mg, Al, Ca, Ti and Mn) in a composite consisting of distorted spinel ferrites (MgFeAlO4 and Fe3O4) and discrete oxides (MgO and Fe2O3), recording a superior oxygen transfer capacity of ∼ 19.8 mmol/gOC during the 900 °C CH4/CO2 cycles. This is attributed to a promoted deep reduction of Fe3+, a high phase segregation of the structure due to oxygen migration, and a strong metal-support interaction between inert MgO and the deeply reduced metallic Fe0. Additionally, the oxygen carrier is capable of catalysing both CH4 reforming and cracking reactions, yielding a high H2/CO molar ratio of 5.3 and a large H2 production (∼70.6 mmol/gOC) in the CH4 reduction stage. In the subsequent CO2 oxidation stage, the lattice oxygen is fully restored, and the Boudouard reaction is also catalysed by the trace cations (Ca, Ti and Mn) to eliminate the coke deposit effectively, which resulted in a total CO production of ∼ 82 mmol/gOC. Meanwhile, the segregated phases are re-integrated together, enabling a successful reversion of the structure for the oxygen carrier and its constantly high and stable activity over cyclic use. © 2025 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ ).
Description
Keywords
Methane, Carbon dioxide, Fly ash, Wastes, Ferrites, Oxidation, Iron, Oxygen, Crystal lattices
Citation
Appiagyei, A. B., Yang, S., Gu, J., Chaffee, A., Liu, J. Z., Gu, Q., & Zhang, L. (2025). Phase segregation-dictated superior Fe-rich ferrite composite for intensified methane dry reforming with CO2 splitting. Chemical Engineering Journal, 507, 160684. doi:10.1016/j.cej.2025.160684