沙特阿卜杜拉国王科技大学Yu Han课题组经过不懈努力，通过对含锆金属有机框架（MOFs）进行相工程，实现了高效渗透压能量转化，并通过直接成像实现了其结构进化。该研究于2024年4月18日发表于国际一流学术期刊《美国化学会杂志》上。

据介绍，在金属有机框架(MOF)中以可控的方式产生结构缺陷对合成提出了重大挑战，同时，确定这些缺陷的类型和分布也是表征的艰巨任务。

在这项研究中，课题组证明了通过使用2-磺酰对苯二甲酸作为配体来合成Zr(或Hf)基MOF，可以很容易地促进从常见的fcu拓扑到罕见的jmt拓扑的晶体相变，仅适用一种简单的混合溶剂策略。jmt相，以一个广泛开放的框架为特征，可以被认为是fcu阶段的衍生物，通过引入缺团簇缺陷而产生。

研究小组已经明确地确定了这两个MOF相，它们的中间态，以及它们形成的新型核壳结构，使用超低剂量高分辨率透射电子显微镜。除了促进相工程，在MOF中加入磺酸基赋予离子选择性，使其适用于通过混合基质膜制造渗透压能量收集应用。含有jmt相MOF的膜在50倍盐度梯度(NaCl: 0.5 M|0.01 M)下表现出异常高的峰值功率密度，达到10.08 W m^-2，超过了5 W m^-2的商业应用阈值，这可归因于这种新型MOF材料的大孔径、广泛的孔隙度和丰富的磺酸基。

附：英文原文

Title: Phase Engineering of Zirconium MOFs Enables Efficient Osmotic Energy Conversion: Structural Evolution Unveiled by Direct Imaging

Author: Cailing Chen, Lingkun Meng, Li Cao, Daliang Zhang, Shuhao An, Lingmei Liu, Jianjian Wang, Guanxing Li, Tingting Pan, Jie Shen, Zhijie Chen, Zhan Shi, Zhiping Lai, Yu Han

Issue&Volume: April 18, 2024

Abstract: Creating structural defects in a controlled manner within metal–organic frameworks (MOFs) poses a significant challenge for synthesis, and concurrently, identifying the types and distributions of these defects is also a formidable task for characterization. In this study, we demonstrate that by employing 2-sulfonylterephthalic acid as the ligand for synthesizing Zr (or Hf)-based MOFs, a crystal phase transformation from the common fcu topology to the rare jmt topology can be easily facilitated using a straightforward mixed-solvent strategy. The jmt phase, characterized by an extensively open framework, can be considered a derivative of the fcu phase, generated through the introduction of missing-cluster defects. We have explicitly identified both MOF phases, their intermediate states, and the novel core–shell structures they form using ultralow-dose high-resolution transmission electron microscopy. In addition to facilitating phase engineering, the incorporation of sulfonic groups in MOFs imparts ionic selectivity, making them applicable for osmotic energy harvesting through mixed matrix membrane fabrication. The membrane containing the jmt-phase MOF exhibits an exceptionally high peak power density of 10.08 W m–2 under a 50-fold salinity gradient (NaCl: 0.5 M|0.01 M), which surpasses the threshold of 5 W m–2 for commercial applications and can be attributed to the combination of large pore size, extensive porosity, and abundant sulfonic groups in this novel MOF material.

DOI: 10.1021/jacs.4c00716

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c00716