High CO₂ concentration in atmosphere causes serious environmental issues, and carbon capture and storage technologies have attracted attention as a means to reduce the atmospheric CO₂ concentration. Metal-organic frameworks (MOFs) can potentially be used for CO₂ adsorption, but their poor stability and microporosity limit their applications. Herein, a novel strategy was proposed to combine a cellulose aerogel and hierarchically-porous MOFs (HP-MOFs) with larger pores. According to this strategy, a series of microcrystalline cellulose/HP-UIO-66-NH₂ hybrid aerogels (MC-HUN-X) was constructed by adding a modulator (monocarboxylic acid, MA), followed by the in-situ growth of HP-UIO-66-NH₂ on a cellulose aerogel. By adjusting the chain length of MA, the structure–function relationship between pore size and the CO₂ adsorption capacity of MC-HUN-X was explored. The results showed that the CO₂ adsorption capacity increased first and then decreased upon increasing the MOFs pore size, while the adsorption selectivity of CO₂ continuously increased. Among all samples, MC-HUN-4 with a moderate pore size had the highest CO₂ adsorption capacity (1.90 mmol/g at 298 K and 1 bar) and adsorption selectivity (13.02 and 2.40 for CO₂/N₂ and CO₂/CH₄). The combination with a cellulose aerogel endowed MC-HUN-X with excellent mechanical stability and reusability.

Graphical abstract

Cellulose/HP-UIO-66-NH₂ hybrid aerogel with larger aperture sizes of MOF showed excellent adsorption capacity and selectivity for CO₂, and the combination with aerogel could effectively improve the mechanical stability and reusability.

中文翻译：

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纤维素气凝胶和分级多孔金属有机框架（HP-MOFs）的新型组合策略以提高二氧化碳吸收性能

大气中的高CO ₂浓度会导致严重的环境问题，而碳捕获和储存技术作为降低大气CO ₂浓度的手段而受到关注。金属有机框架（MOFs）可潜在地用于CO ₂吸附，但其较差的稳定性和微孔性限制了它们的应用。在此，提出了一种将纤维素气凝胶和分级多孔 MOF (HP-MOF) 与更大孔隙相结合的新策略。根据该策略，通过添加调节剂（一元羧酸，MA），然后原位生长HP，构建了一系列微晶纤维素/HP-UIO-66-NH ₂杂化气凝胶（MC-HUN-X）。 -UIO-66-NH ₂在纤维素气凝胶上。通过调节MA的链长，探讨了MC-HUN-X孔径与CO ₂吸附量之间的结构-功能关系。结果表明，随着MOFs孔径的增大，CO ₂的吸附容量先增大后减小，而CO ₂的吸附选择性不断增大。在所有样品中，中等孔径的 MC-HUN-4 具有最高的 CO ₂吸附容量（298 K 和 1 bar 时为 1.90 mmol/g）和吸附选择性（CO ₂ /N ₂和 CO ₂ /分别为 13.02 和 2.40）。_第四频道）。与纤维素气凝胶的结合使 MC-HUN-X 具有出色的机械稳定性和可重复使用性。

图形概要

较大孔径MOF的Cellulose/HP-UIO-66-NH _{2杂化气凝胶对CO 2}表现出优异的吸附能力和选择性，与气凝胶的结合可有效提高机械稳定性和可重复使用性。