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Reduction kinetics of SrFeO3−δ/CaO·MnO nanocomposite as effective oxygen carrier for chemical looping partial oxidation of methane. Front Chem Sci Eng 2022. [DOI: 10.1007/s11705-022-2188-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Sr1-xKxFeO3 Perovskite Catalysts with Enhanced RWGS Reactivity for CO2 Hydrogenation to Light Olefins. ATMOSPHERE 2022. [DOI: 10.3390/atmos13050760] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The catalytic hydrogenation of CO2 to light olefins (C2–C4) is among the most practical approaches to CO2 utilization as an essential industrial feedstock. To achieve a highly dispersed active site and enhance the reactivity of the reverse water–gas shift (RWGS) reaction, ABO3-type perovskite catalysts Sr1-xKxFeO3 with favorable thermal stability and redox activity are reported in this work. The role of K-substitution in the structure–performance relationship of the catalysts was investigated. It indicated that K-substitution expedited the oxygen-releasing process of the SrFeO3 and facilitated the synchronous formation of active-phase Fe3O4 for the reverse water–gas shift (RWGS) reaction and Fe5C2 for the Fischer–Tropsch synthesis (FTS). At the optimal substitution amount, the conversion of CO2 and the selectivity of light olefins achieved 30.82% and 29.61%, respectively. Moreover, the selectivity of CO was up to 45.57% even when H2/CO2=4 due to CO2-splitting reactions over the reduced Sr2Fe2O5. In addition, the reversibility of perovskite catalysts ensured the high dispersion of the active-phase Fe3O4 and Fe5C2 in the SrCO3 phase. As the rate-determining step of the CO2 hydrogenation reaction to light olefins over Sr1-xKxFeO3 perovskite catalysts, FTS should be further tailored by partial substitution of the B site. In sum, the perovskite-derived catalyst investigated in this work provided a new idea for the rational design of a catalyst for CO2 hydrogenation to produce light olefins.
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Tian M, Wang C, Han Y, Wang X. Recent Advances of Oxygen Carriers for Chemical Looping Reforming of Methane. ChemCatChem 2021. [DOI: 10.1002/cctc.202001481] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Ming Tian
- CAS Key Laboratory of Science and Technology on Applied Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences 457 Zhongshan Road Dalian 116023 P. R. China
| | - Chaojie Wang
- CAS Key Laboratory of Science and Technology on Applied Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences 457 Zhongshan Road Dalian 116023 P. R. China
- University of Chinese Academy of Sciences 19(A) Yuquan Road Shijingshan District Beijing 100049 P. R. China
| | - Yujia Han
- CAS Key Laboratory of Science and Technology on Applied Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences 457 Zhongshan Road Dalian 116023 P. R. China
- University of Chinese Academy of Sciences 19(A) Yuquan Road Shijingshan District Beijing 100049 P. R. China
| | - Xiaodong Wang
- CAS Key Laboratory of Science and Technology on Applied Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences 457 Zhongshan Road Dalian 116023 P. R. China
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Abstract
Methane activation chemistry, despite being widely reported in literature, remains to date a subject of debate. The challenges in this reaction are not limited to methane activation but extend to stabilization of the intermediate species. The low C-H dissociation energy of intermediates vs. reactants leads to CO2 formation. For selective oxidation, nature presents methane monooxygenase as a benchmark. This enzyme selectively consumes methane by breaking it down into methanol. To assemble an active site similar to monooxygenase, the literature reports Cu-ZSM-5, Fe-ZSM-5, and Cu-MOR, using zeolites and systems like CeO2/Cu2O/Cu. However, the trade-off between methane activation and methanol selectivity remains a challenge. Density functional theory (DFT) calculations and spectroscopic studies indicate catalyst reducibility, oxygen mobility, and water as co-feed as primary factors that can assist in enabling higher selectivity. The use of chemical looping can further improve selectivity. However, in all systems, improvements in productivity per cycle are required in order to meet the economical/industrial standards.
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