Redox-mediated reverse water gas shift integrated with ammonia cracking over Ni/La0.75Sr0.25Cr0.5Mn0.5O3−δ
NH3 and CO2 can react to produce syngas (H2 + CO), which serves as a feedstock for the production of chemicals or synthetic fuels. Combining NH3 cracking (NH3 → 0.5N2 + 1.5H2) and the redox-mediated reverse water gas shift reaction (RWGS, CO2 + H2 → CO + H2O), we propose the “NH3-RWGS” process in a...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-05-01
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| Series: | Chemical Engineering Journal Advances |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2666821125000109 |
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| Summary: | NH3 and CO2 can react to produce syngas (H2 + CO), which serves as a feedstock for the production of chemicals or synthetic fuels. Combining NH3 cracking (NH3 → 0.5N2 + 1.5H2) and the redox-mediated reverse water gas shift reaction (RWGS, CO2 + H2 → CO + H2O), we propose the “NH3-RWGS” process in a two-reactor system that can produce N2-free syngas without requiring a downstream gas separation step. We investigate the role of La0.75Sr0.25Cr0.5Mn0.5O3−δ (LSCM) in the redox-mediated RWGS, combined with a stabilized Ni catalyst to impart NH3 cracking functionality. The mixture of LSCM and Ni catalyst at a weight ratio of 10:1 increases the NH3 cracking activity fivefold compared to using only LSCM. Because the reduction of LSCM proceeds through a two-step mechanism that requires the prior cracking of NH3, it also substantially increases the redox reactivity of LSCM. The Ni catalyst exhibits undesirable nitrogen uptake at ∼500 °C, and the redox capacity of LSCM with NH3 and CO2 decreases with temperature. Therefore, the process is best implemented at ∼600 °C. Under these conditions, the application of the “NH3-RWGS” process with mixtures of LSCM and Ni catalyst is promising to produce high-quality, N2-free syngas directly from NH3 and CO2. |
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| ISSN: | 2666-8211 |