N-donating and water-resistant Zn-carboxylate frameworks for humid carbon dioxide capture from flue gas

Carbon capture from flue gases is one of the crucial routines for reducing current CO₂ emissions and mitigating the greenhouse effect. Metal-organic frameworks (MOFs) have received a lot of interest as efficient solid adsorbents for CO₂/N₂ separation in flue gas treatment. However, many MOF materials are susceptible to the presence of water vapor, which has a significant impact on their adsorption efficacy and moisture stability. Here in this work, we reported two pillar-layered Zn-MOFs with N-donors, i.e., Zn₂(TRZ)₂(Fuma) and Zn₂(TRZ)₂(BDC), which demonstrated high CO₂ uptakes (3.92 and 1.52 mmol/g) and CO₂/N₂ (132 and 20.5) adsorption selectivities at 298 K and 101 kPa, among the best comprehensive results reported by far. After seven days of exposure to a 100 % RH environment, it was found that, the Zn-N pillar contributes to the robust structure of MOFs. Furthermore, in-depth theoretical calculations indicated the guest-framework interactions, and dynamic sorption tests confirmed high working capacities (2.78 and 1.14 mmol/g), sufficient water stability and remarkable cycling performance of the studied MOFs under humid ambient conditions. We believe this work provides a routine to prepare robust and promising candidates to address the challenge in carbon capture under humid conditions.