Koupepidou Kyriaki, Subanbekova Aizhamal, Zaworotko Michael J
Bernal Institute, Department of Chemical Sciences, University of Limerick, Limerick V94T9PX, Republic of Ireland.
Chem Commun (Camb). 2025 Feb 13;61(15):3109-3126. doi: 10.1039/d4cc05393a.
Physisorbents are poised to address global challenges such as CO capture, mitigation of water scarcity and energy-efficient commodity gas storage and separation. Rigid physisorbents, those adsorbents that retain their structures upon gas or vapour exposure, are well studied in this context. Conversely, cooperatively flexible physisorbents undergo long-range structural transformations stimulated by guest exposure. Discovered serendipitously, flexible adsorbents have generally been regarded as scientific curiosities, which has contributed to misconceptions about their potential utility. Recently, increased scientific interest and insight into the properties of flexible adsorbents has afforded materials whose performance suggests that flexible adsorbents can compete with rigid adsorbents for both storage and separation applications. With respect to gas storage, adsorbents that undergo guest-induced phase transformations between low and high porosity phases in the right pressure range can offer improved working capacity and heat management, as exemplified by studies on adsorbed natural gas storage. For gas and vapour separations, the very nature of flexible adsorbents means that they can undergo induced fit mechanisms of guest binding, the adsorbent can adapt to a specific adsorbate. Such flexible adsorbents have set several new benchmarks for certain hydrocarbon separations in terms of selectivity and separation performance. This Feature Article reviews progress made by us and others towards the crystal engineering (design and control) of flexible adsorbents and addresses several of the myths that have emerged since their initial discovery, particularly with respect to those performance parameters of relevance to natural gas storage, water harvesting and hydrocarbon gas/vapour separation.
物理吸附剂有望应对全球挑战，如二氧化碳捕集、缓解水资源短缺以及高效存储和分离商品气体。刚性物理吸附剂，即在气体或蒸汽暴露下保持其结构的吸附剂，在这方面已得到充分研究。相反，协同柔性物理吸附剂会因客体暴露而发生长程结构转变。柔性吸附剂是偶然发现的，通常被视为科学上的奇闻趣事，这导致了对其潜在用途的误解。最近，对柔性吸附剂性能的科学兴趣和洞察力不断增加，使得一些材料的性能表明，柔性吸附剂在存储和分离应用方面可以与刚性吸附剂相竞争。关于气体存储，在合适的压力范围内，能在低孔隙率和高孔隙率相之间发生客体诱导相变的吸附剂，可以提供更高的工作容量和热管理能力，吸附天然气存储的研究就是例证。对于气体和蒸汽分离，柔性吸附剂的本质意味着它们可以经历客体结合的诱导契合机制，即吸附剂可以适应特定的吸附质。这种柔性吸附剂在选择性和分离性能方面为某些烃类分离设定了几个新的基准。这篇专题文章回顾了我们和其他人在柔性吸附剂的晶体工程（设计和控制）方面取得的进展，并探讨了自其最初发现以来出现的一些误解，特别是关于那些与天然气存储、水收集和烃类气体/蒸汽分离相关的性能参数。
