Observation of distinct structural transformation between sI and sH gas hydrates and their kinetic properties during CO₂ capture from N₂ + CO₂

sH hydrate has a deal of attention as an attractive medium of gas storage and separation due to its relatively milder formation condition and higher storage capacity, and thus sH hydrate has focused on the potential application in the post-combustion CO₂ capture. Nonetheless, in-depth investigations on the thermodynamic stability of sH hydrate of N₂ + CO₂ and the possible occurrence of structural transformation during the process have not yet been addressed. Since the gas hydrate-based CO₂ capture technology involves stepwise enrichments of CO₂ through iterative formation-dissociation processes of CO₂ hydrate, knowledge about the thermodynamic stability between sI and sH hydrates in the presence of various N₂:CO₂ ratios and their kinetic properties is important for designing the gas hydrate-based CO₂ separation process. Here, we explored sI and sH hydrates of 3,3-dimethyl-1-butanol + N₂ + CO₂ focusing on their structural stability and structure-dependent kinetic properties. The experimental data including P–T phase equilibria, induction time, gas uptake, and CO₂ separation factor are provided with a structural analysis via synchrotron high-resolution powder diffraction.