离子环境对提高沸石孔中反应分子活性的作用，这一成果由德国慕尼黑工业大学Johannes A. Lercher研究小组经过不懈努力而取得。 相关论文发表在2021年5月6日出版的《科学》杂志上。

该工作中，利用环己醇在水中H-MFI上的分子内脱水，该团队定量地证明了高离子强度的存在提高了反应速率，以及这种策略的潜在局限性。

据悉，通过调整催化活性位点周围的分子环境，可以通过迄今尚未探索的途径提高催化反应性。在沸石中，水的存在通过形成水合氢离子和带负电荷的框架铝四面体创造了一个离子环境。由沸石的铝浓度决定的高的阳离子-阴离子对的密度导致了高的局部离子强度，增加了吸附和不带电的有机反应物的过量化学势。带电的过渡态(例如碳正离子)是稳定的，降低了能量位垒并导致更高的反应速率。

附：英文原文

Title: Role of the ionic environment in enhancing the activity of reacting molecules in zeolite pores

Author: Niklas Pfriem, Peter H. Hintermeier, Sebastian Eckstein, Sungmin Kim, Qiang Liu, Hui Shi, Lara Milakovic, Yuanshuai Liu, Gary L. Haller, Eszter Baráth, Yue Liu, Johannes A. Lercher

Issue&Volume: 2021/05/06

Abstract: Tailoring the molecular environment around catalytically active site allows to enhance catalytic reactivity via a hitherto unexplored pathway. In zeolites, the presence of water creates an ionic environment via formation of hydrated hydronium ions and the negatively charged framework Al tetrahedra. The high density of cation-anion pairs determined by the aluminum concentration of a zeolite induces a high local ionic strength that increases the excess chemical potential of sorbed and uncharged organic reactants. Charged transition states (carbocations for example) are stabilized, reducing the energy barrier and leading to higher reaction rates. Using the intramolecular dehydration of cyclohexanol on H-MFI in water, we show quantitatively the enhancement of the reaction rate by the presence of high ionic strength as well as potential limitations of this strategy.

DOI: 10.1126/science.abh3418

Source: https://science.sciencemag.org/content/early/2021/05/05/science.abh3418