电子显微镜显示金属有机框架中的不均吸附和并发缺陷形成
Ying Liu1, Dong Liu1, Zhaohui Liu1
1Multi-scale Porous Materials Center, Institute of Advanced Interdisciplinary Studies & School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, P. R. China.
Journal of the American Chemical Society
|January 24, 2025
概括
在MFM-300的分子 (I2) 吸附是不均的,即使在和. STEM成像显示存在空洞和充满的通道,潜在的三螺旋结构和持续的框架缺陷.
科学领域:
- 材料科学
- 纳米技术
- 化学学
背景情况:
- 吸附等热量是研究气体吸收的标准,但不能揭示空间变化.
- 由于强烈的吸附剂-吸附剂相互作用,吸附的不均性可能会出现.
- 金属有机框架 (MOF) 为吸附研究提供可调节的多孔结构.
研究的目的:
- 想象和理解分子 (I2) 吸附在MFM-300(Sc) MOF中的空间分布.
- 研究MOF中的I2吸附的结构后果.
- 制定控制MOF释放的战略.
主要方法:
- 高分辨率扫描传输电子显微镜 (STEM) 用于在MFM-300中直接可视化.
- 图像模拟以解释观察到的I2包装结构.
- 开发表面活性剂封闭策略,以尽量减少I2的释放.
主要成果:
- 在MFM-300 (Sc) 中的吸附在本质上是不均的,在所有吸收水平上观察到不同的通道填充.
- 即使在和 (23I原子/单元细胞) 时,MOF通道也从几乎空到密集填充.
- 图像模拟表明局部形成的三螺旋I2结构 (高达142I原子/单元细胞).
- 在MOF框架中引起了持续的结构缺陷 (边缘突变,堆叠缺陷).
- 一种表面活性剂限制策略有效地减少了I2的释放,由STEM证实.
结论:
- 通过STEM直接可视化克服了异质吸附系统的吸附等温的局限性.
- MFM-300(Sc) 呈现出复杂,不均的I2吸收行为,可能形成新的结构.
- I2吸附可以在结构上修改MOF,从而产生持续在脱附后的缺陷.
- 表面活性剂的限制提供了一种可行的方法来稳定MOF中的吸附物种.
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