Ultramicroporous Metal–Organic Framework Qc-5-Cu for Highly Selective Adsorption of CO2 from C2H4 Stream

Template-Mediated Synthesis of Hierarchically Porous Metal–Organic Frameworks for Efficient CO2/N2 Separation

Carbon dioxide (CO₂) is generally unavoidable during the production of fuel gases such as hydrogen (H₂) from steam reformation and syngas composed of carbon monoxide (CO) and hydrogen (H₂). Efficient separation of CO₂ from these gases is highly important to improve the energetic utilization efficiency and prevent poisoning during specific applications. Metal–organic frameworks (MOFs), featuring ordered porous frameworks, high surface areas and tunable pore structures, are emerging porous materials utilized as solid adsorbents for efficient CO₂ capture and separation. Furthermore, the construction of hierarchical MOFs with micropores and mesopores could further promote the dynamic separation processes, accelerating the diffusion of gas flow and exposing more adsorptive pore surface. Herein, we report a simple, efficient, one-pot template-mediated strategy to fabricate a hierarchically porous CuBTC (CuBTC-Water, BTC = 1,3,5-benzenetricarboxylate) for CO₂ separation, which demonstrates abundant mesopores and the superb dynamic separation ability of CO₂/N₂. Therefore, CuBTC-Water demonstrated a CO₂ uptake of 180.529 cm³ g⁻¹ at 273 K and 1 bar, and 94.147 cm³ g⁻¹ at 298 K and 1 bar, with selectivity for CO₂/N₂ mixtures as high as 56.547 at 273 K, much higher than microporous CuBTC. This work opens up a novel avenue to facilely fabricate hierarchically porous MOFs through one-pot synthesis for efficient dynamic CO₂ separation.

One-step ethylene production from a four-component gas mixture by a single physisorbent

One-step adsorptive purification of ethylene (C₂H₄) from four-component gas mixtures comprising acetylene (C₂H₂), ethylene (C₂H₄), ethane (C₂H₆) and carbon dioxide (CO₂) is an unmet challenge in the area of commodity purification. Herein, we report that the ultramicroporous sorbent Zn-atz-oba (H₂oba = 4,4-dicarboxyl diphenyl ether; Hatz = 3-amino-1,2,4-triazole) enables selective adsorption of C₂H₂, C₂H₆ and CO₂ over C₂H₄ thanks to the binding sites that lie in its undulating pores. Molecular simulations provide insight into the binding sites in Zn-atz-oba that are responsible for coadsorption of C₂H₂, C₂H₆ and CO₂ over C₂H₄. Dynamic breakthrough experiments demonstrate that the selective binding exhibited by Zn-atz-oba can produce polymer-grade purity (>99.95%) C₂H₄ from binary (1:1 for C₂H₄/C₂H₆), ternary (1:1:1 for C₂H₂/C₂H₄/C₂H₆) and quaternary (1:1:1:1 for C₂H₂/C₂H₄/C₂H₆/CO₂) gas mixtures in a single step.