Xiang et al. (2023): Synthesis of stable single-crystalline carbon dioxide clathrate powder by pressure swing crystallization

Zhiling Xiang, Congyan Liu, Chunhui Chen, Xin Xiao, Thien S. Nguyen, Cafer T. Yavuz, Qiang Xu, Bo Liu IN: Cell Reports Physical Science 4, 101383, https://doi.org/10.1016/j.xcrp.2023.101383

Here, the authors report the pressure swing crystallization of CO₂ in a single-crystalline guanidinium sulfate-based clathrate salt under practical conditions of 52 kPa and 298 K, with a high CO₂ density (0.252 g cm⁻³) and capacity (17 wt %). The captured CO₂ is released as a pure stream through moderate means of pressure or temperature stimulation, all while the desorbed Gua₂SO₄ is ready for another cycle. The clathrate is selective exclusively to CO₂ even in the presence of common flue gas components, such as water vapor and N₂, owing to the specific electrostatic interaction between the CO₂ and guanidinium cations. The mechanism unraveled through single-crystal studies is distinctively different from physisorption or chemisorption, opening up a promising venue for future carbon capture and storage technologies through rapid CO₂ solidification using an abundant salt.

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