Carbon dioxide sorption in a nanoporous octahedral molecular sieve

Abstract

We have performed first-principles density functional theory calculations, incorporated with van der Waals interactions, to study CO2 adsorption and diffusion in nanoporous solid -OMS-2 (Octahedral Molecular Sieve). We found the charge, type, and mobility of a cation, accommodated in a porous OMS-2 material for structural stability, can affect not only the OMS-2 structural features but also CO2 sorption performance. This paper targets K + , Na + , and Ba 2+ cations. First-principles energetics and electronic structure calculations indicate that Ba 2+ has the strongest interaction with the OMS-2 porous surface due to valence electrons donation to the OMS-2 and molecular orbital hybridization. However, the Ba-doped OMS-2 has the worst CO2 uptake capacity. We also found evidence of sorption hysteresis in the K-and Nadoped OMS-2 materials.

First-principles study of carbon capture and storage properties of porous MnO2 octahedral molecular sieve OMS-5

“…With β = ~ 97 0 and α = γ = ~90°, the OMS-5 cell remains monoclinic in the presence of Na + cations. However, the cell volume shrinks by 0.3% with a low concentration of Na + cations and 0.8% with a high concentration of Na + cations, which also happens in the OMS-2 materials (Williamson et al , 2015). The volume decrease is the concequence of the shorter tunnel length along the b axis.…”

“…These data confirm that OMS-5 demonstrates semiconducting behavior. Like OMS-2, the DoS of OMS-5 shifts to the lower energy values in the presence of Na + cations (Williamson et al ., 2015). This shift stems from the Na + donating electrons to the OMS-5.…”

“…Our previous work with OMS-2 showed that cations could stabilize not only the tunnel size and shape of the porous structure, but also play a role as a “gate keeper” to induce an energy barrier for CO 2 to diffuse along the tunnel (Williamson et al , 2015). The larger tunnel size of the OMS-5 structure would undoubtedly affect its adsorption mechanism of CO 2 , so we focus on three following scenarios: Scenario I: OMS-5 without cations Scenario II: OMS-5 with a low concentration of Na + cations Scenario III: OMS-5 with a high concentration of Na + cations…”

“…In comparison between K + and other types of cations, we found the charge, type, and mobility of the cation could affect not only the OMS-2 structural features but also CO 2 sorption performance, implying that modifying these features could optimize the carbon capture properties of OMS-2. We extended our DFT-based energetic and electronic structure calculations to Na + and Ba 2+ cations for comparison with K + (Williamson et al , 2015). Because of the higher charge and more electrons donated to the MnO 2 , Ba 2+ had a more than twice stronger interaction with the OMS-2 porous surface than both K + and Na + did.…”

Research Progress on CO2 Capture, Utilization, and Storage (CCUS) Based on Micro-Nano Fluidics Technology

“…Existing research has demonstrated the potential of micro-nanofluidic technology in CO 2 capture. Currently, CO 2 capture technologies mainly include absorption, adsorption [43][44][45], and membrane separation. Absorption methods involve physical and chemical absorption, which utilize organic solvents or alkaline solutions with high solubility, selectivity, and stability to separate CO 2 .…”