Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States.
School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, P. R. China.
Nano Lett. 2020 Mar 11;20(3):1774-1780. doi: 10.1021/acs.nanolett.9b04997. Epub 2020 Feb 7.
We studied coordination-dependent surfactant binding on shaped MOF nanocrystals. Cetyltrimethylammonium bromide (CTAB) on the surface of ZIF-8 was used as a model system. Infrared spectroscopic analysis and molecular dynamics simulations reveal different coordination environments for Zn nodes on {100} and {110} facets, resulting in different CTAB adsorption. We found that we are able to fine-tune the ratio of {100} and {110} facets in the nanocrystals. We also observed that once the MOF nanocrystals are enclosed by pure {110} facets growth along the {100} facets is terminated because the MOF nanocrystal has no surface area for CTAB adsorption. Growth can then be reinitiated through the etching of these rhombic dodecahedral nanocrystals to form a small amount of undercoordinated sites. This work represents the first systematic study of the design principles underpinning the synthesis of shaped MOF nanocrystals.
我们研究了在成型 MOF 纳米晶体上的依赖于配位的表面活性剂结合。我们以 ZIF-8 表面上的十六烷基三甲基溴化铵（CTAB）作为模型体系。红外光谱分析和分子动力学模拟揭示了{100}和{110}面的 Zn 节点的不同配位环境，导致 CTAB 吸附的不同。我们发现我们能够微调纳米晶体中{100}和{110}面的比例。我们还观察到，一旦 MOF 纳米晶体被纯{110}面封闭，沿着{100}面的生长就会终止，因为 MOF 纳米晶体没有 CTAB 吸附的表面积。然后可以通过刻蚀这些菱十二面体纳米晶体来重新开始生长，从而形成少量配位不足的位点。这项工作代表了对合成成型 MOF 纳米晶体的设计原则的首次系统研究。
