National Collaborative Innovation Center for Nuclear Waste and Environmental Safety, School of National Defence Science & Technology, Southwest University of Science and Technology, Mianyang, PR China.
SUSTech Core Research Facilities, Southern University of Science and Technology, Shenzhen, PR China.
Nat Commun. 2021 Jul 23;12(1):4483. doi: 10.1038/s41467-021-24830-1.
Zeolitic imidazolate frameworks (ZIFs) are very useful as high-capacity iodine (I) adsorbents. The adsorption performance is usually probed by measuring a statistical average property over an entire sample consisting of a large number of ZIF particles, leaving the interparticle heterogeneity information among individuals. Here we report a dark-field microscopy (DFM) method to visualize gaseous I adsorption on single ZIF-90 particles in situ and in real time. The adsorption of I is found to alter the scattering spectrum of ZIF-90 particles, inducing a distinct color change from bluewhite to yellow. According to correlating the adsorption amount of gaseous I with the change of B value from DFM images, we quantitatively image the adsorption process and estimate the related kinetic parameters at the single particle level. Single particle measurements clarify the large particle-to-particle heterogeneity in adsorption reactivity and significant adsorption activity improvement of ZIF-90 after introduction of linker defects, which provides a microscopic understanding of the structure-activity relationship. We further demonstrate the capacity of this strategy for studying gaseous I adsorption on single ZIF-91 particle as a derivative of ZIF-90 to illustrate the generality.
沸石咪唑酯骨架（ZIFs）作为高容量碘（I）吸附剂非常有用。通常通过测量由大量 ZIF 颗粒组成的整个样品的统计平均性质来探测吸附性能，而忽略个体之间的颗粒间异质性信息。在这里，我们报告了一种暗场显微镜（DFM）方法，用于原位和实时可视化单个 ZIF-90 颗粒上的气态 I 吸附。发现 I 的吸附会改变 ZIF-90 颗粒的散射光谱，导致从蓝白色到黄色的明显颜色变化。根据将气态 I 的吸附量与 DFM 图像中 B 值的变化相关联，我们定量地对吸附过程进行成像，并估计单个颗粒水平上的相关动力学参数。单颗粒测量清楚地表明了吸附反应性在颗粒间的巨大异质性，以及在引入连接缺陷后 ZIF-90 的吸附活性显著提高，这为结构-活性关系提供了微观理解。我们进一步证明了该策略用于研究气态 I 在作为 ZIF-90 衍生物的单个 ZIF-91 颗粒上的吸附的能力，以说明其普遍性。
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