气候变化领域集成服务门户(CCPortal): Peering into buried interfaces with X-rays and electrons to unveil MgCO3 formation during CO2 capture in molten salt-promoted MgO

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DOI	10.1073/pnas.2103971118
	Peering into buried interfaces with X-rays and electrons to unveil MgCO3 formation during CO2 capture in molten salt-promoted MgO
	Bork A.H.; Rekhtina M.; Willinger E.; Castro-Fernández P.; Drnec J.; Abdala P.M.; Müller C.R.
发表日期	2021
ISSN	0027-8424
卷号	118 期号:26
英文摘要	The addition of molten alkali metal salts drastically accelerates the kinetics of CO2 capture by MgO through the formation of MgCO3. However, the growth mechanism, the nature of MgCO3 formation, and the exact role of the molten alkali metal salts on the CO2 capture process remain elusive, holding back the development of more-effectiveMgO-based CO2 sorbents. Here, we unveil the growth mechanism of MgCO3 under practically relevant conditions using a well-defined, yet representative, model system that is a MgO(100) single crystal coated with NaNO3. The model system is interrogated by in situ X-ray reflectometry coupled with grazing incidence X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. When bare MgO(100) is exposed to a flow of CO2, a noncrystalline surface carbonate layer of ca. 7-Å thickness forms. In contrast, when MgO(100) is coated with NaNO3, MgCO3 crystals nucleate and grow. These crystals have a preferential orientation with respect to the MgO(100) substrate, and form at the interface between MgO(100) and the molten NaNO3. MgCO3 grows epitaxially with respect to MgO(100), and the lattice mismatch between MgCO3 and MgO is relaxed through lattice misfit dislocations. Pyramid-shaped pits on the surface ofMgO, in proximity to and below the MgCO3 crystals, point to the etching of surface MgO, providing dissolved [Mg2+ O2-] ionic pairs forMgCO3 growth. Our studies highlight the importance of combining X-rays and electron microscopy techniques to provide atomic to micrometer scale insight into the changes occurring at complex interfaces under reactive conditions. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Carbonate; CO2; Interfaces; Microscopy; X-rays
语种	英语
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/238502
作者单位	Laboratory of Energy Science and Engineering, Department of Mechanical and Process Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Zürich, 8092, Switzerland; European Synchrotron Radiation Facility, Grenoble, 38000, France
推荐引用方式 GB/T 7714	Bork A.H.,Rekhtina M.,Willinger E.,et al. Peering into buried interfaces with X-rays and electrons to unveil MgCO3 formation during CO2 capture in molten salt-promoted MgO[J],2021,118(26).
APA	Bork A.H..,Rekhtina M..,Willinger E..,Castro-Fernández P..,Drnec J..,...&Müller C.R..(2021).Peering into buried interfaces with X-rays and electrons to unveil MgCO3 formation during CO2 capture in molten salt-promoted MgO.Proceedings of the National Academy of Sciences of the United States of America,118(26).
MLA	Bork A.H.,et al."Peering into buried interfaces with X-rays and electrons to unveil MgCO3 formation during CO2 capture in molten salt-promoted MgO".Proceedings of the National Academy of Sciences of the United States of America 118.26(2021).