In this study, high yields of CO are reported from CO2using the silica (SiO2) supported perovskite oxide, La0.75Sr0.25FeO3(LSF), composites in the reverse water gas shift chemical looping (RWGS‐CL) process. XRD patterns of materials formed upon adding SBA‐15 to the perovskite sol‐gel precursor solution indicated successful formation of an orthorhombic perovskite oxide structure in the composites. The total surface area increased by ∼300 % with the addition of 50 % LSF to SBA‐15 by mass and surface accessibility of perovskite oxide crystallites was verified by CO2chemisorption and XPS measurements. Composite materials achieved up to a factor of 10 increases in CO yields (∼3.5 vs 0.35 mmol CO/gLSF) compared to pure LSF through six consecutive RWGS‐CL cycles at 700 °C. Following these RWGS‐CL cycles, XRD Scherrer analyses showed that the perovskite oxide in the composite material decreased in crystallite size. This approach to synthesis of supported perovskite oxides is expected to be valuable for large‐scale CO2conversion by RWGS‐CL.
Earth abundant perovskite oxides for low temperature CO 2 conversion
Conversion of CO 2 in a scalable technology has the potential for enormous energy and environmental impact but remains a challenge. We present several stable, earth abundant perovskite oxide materials for the reverse water gas shift chemical looping (RWGS-CL) process as a potential solution for this CO 2 mitigation problem. This material and process combination circumvents issues plaguing other emerging technologies, viz. poor rates of CO 2 conversion, high operation temperatures, use of precious metal catalysts, or combinations thereof. Using DFT-calculated oxygen vacancy formation energy, a key descriptor for the RWGS-CL process, we have successfully predicted several earth abundant perovskite oxides with high CO 2 conversion capability. We simultaneously achieved 100% selective CO generation from CO 2 at the highest known rates (∼160 μmoles per min per gram perovskite oxide) at record low process temperatures of 450–500 °C using lanthanum and calcium based perovskite oxides. These materials are stable over several RWGS-CL cycles, enabling industrial implementation.
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- NSF-PAR ID:
- 10077221
- Date Published:
- Journal Name:
- Energy & Environmental Science
- Volume:
- 11
- Issue:
- 3
- ISSN:
- 1754-5692
- Page Range / eLocation ID:
- 648 to 659
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/C7EE03383D
