从溶液的角度来看,M (M = Zr,Hf,Ce,Th) UiO-66 MOF 的酸性稳定性
Makenzie T Nord1, Alyson S Plaman2, Lev N Zakharov1
1Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, United States.
ACS applied materials & interfaces
|March 27, 2025
概括
这项研究揭示了UiO-66金属有机框架 (MOF) 在酸中如何溶解,显示Zr,Hf和Ce-UiO-66形成可溶性六合体结,而Th-UiO-66完全分解. 这项工作推进了缺陷工程和合式MOF设计.
科学领域:
- 材料科学 材料科学 材料科学
- 化学 化学 化学
- 纳米技术纳米技术
背景情况:
- UiO-66是一种突出的金属有机框架 (MOF),以其稳定性而闻名.
- 之前的研究重点是通过酸处理的固态稳定性和缺陷工程.
- 在各种酸中UiO-66的溶解行为和溶液特异性仍未得到充分研究.
研究的目的:
- 研究不同UiO-66 (M=Zr,Ce,Hf,Th) 框架在酸和酸中的溶解途径和溶液特异化.
- 为了描述由此产生的溶解物种和固体沉物.
- 了解对缺陷工程,合MOF设计和材料组装的影响.
主要方法:
- 用不同度的酸和酸对UiO-66 (Zr,Hf,Ce,Th) 的处理.
- 使用包括X射线散射 (SAXS) 在内的技术对溶解物种和固体产品进行表征.
- 结晶学分析以确定新的结构形式.
主要成果:
- Zr,Hf和Ce-UiO-66在2-10M/酸中完全分解成可溶性六合体结节和沉结节.
- Th-UiO-66经历完整的节点侵蚀,形成与酸盐结合的Th-单体链.
- 确定了六合体框架的新晶体结构 ([Ce6O4(OH) 4 ((H2O) ((HCOO) 12) ·4.8H2O和[Hf6O4 ((OH) 4 ((H2O) 4 ((HCOO) 12) Cl2·8H2O).
- 对合物SAXS分析显示,与溶解的六合素共存的聚合物中保留了MOF顺序.
- 发现Zr6/Hf6在2M酸中的可溶性极限为~0.2M.
- 漏百分比差异很大,Ce具有高溶解度 (57%),归因于氧化还原活性,Zr在矿物酸中比Hf具有更大的可变性.
结论:
- 该研究阐明了基于金属节点的UiO-66框架的独特溶解机制.
- 结果为控制缺陷工程和合物材料合成中的应用提供了对控制MOF溶解的关键见解.
- 突出了Zr和Hf氧气集群的不同溶解度和特异化行为.
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