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Abstract In this work, a new type of multifunctional materials (MFMs) called self‐regenerative Ni‐doped CaTiO3/CaO is introduced for the integrated CO2capture and dry reforming of methane (ICCDRM). These materials consist of a catalytically active Ni‐doped CaTiO3and a CO2sorbent, CaO. The article proposes a concept where the Ni catalyst can be regenerated in situ, which is crucial for ICCDRM. Exsolved Ni nanoparticles are evenly distributed on the surface of CaTiO3under H2or CH4, and are re‐dispersed back into the CaTiO3lattice under CO2. The Ni‐doped CaTiO3/CaO MFMs show stable CO2capture capacity and syngas productivity for 30 cycles of ICCDRM. The presence of CaTiO3between CaO grains prevents CaO/CaCO3thermal sintering during carbonation and decarbonation. Moreover, the strong interaction of CaTiO3with exsolved Ni mitigates severe accumulation of coke deposition. This concept can be useful for developing MFMs with improved properties that can advance integrated carbon capture and conversion.
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Precision Calcination Mechanism of CaCO 3 to High‐Porosity Nanoscale CaO CO 2 Sorbent Revealed by Direct In Situ Observations
Abstract Deploying energy storage and carbon capture at scale is hindered by the substantial endothermic penalty of decomposing CaCO3to CaO and CO2, and the rapid loss of CO2absorption capacity by CaO sorbent particles due to sintering at the high requisite decomposition temperatures. The decomposition reaction mechanism underlying sorbent deactivation remains unclear at the atomic level and nanoscale due to past reliance on postmortem characterization methods with insufficient spatial and temporal resolution. Thus, elucidating the important CaCO3decomposition reaction pathway requires direct observation by time‐resolved (sub‐)nanoscale methods. Here, chemical and structural dynamics during the decomposition of CaCO3nanoparticles to nanoporous CaO particles comprising high‐surface‐area CaO nanocrystallites are examined. Comparing in situ transmission electron microscopy (TEM) and synchrotron X‐ray diffraction experiments gives key insights into the dynamics of nanoparticle calcination, involving anisotropic CaCO3thermal distortion before conversion to thermally dilated energetically stable CaO crystallites. Time‐resolved TEM uncovered a novel CaO formation mechanism involving heterogeneous nucleation at extended CaCO3defects followed by sweeping reaction front motion across the initial CaCO3particle. These observations clarify longstanding, yet incomplete, reaction mechanisms and kinetic models lacking accurate information about (sub‐)nanoscale dynamics, while also demonstrating calcination of CaCO3without sintering through rapid heating and precise temperature control.
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- PAR ID:
- 10499200
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials Interfaces
- Volume:
- 11
- Issue:
- 14
- ISSN:
- 2196-7350
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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