在高密度无形 Zn/Co-ZIF-4 中的玻璃过渡
Zijuan Du1,2,3, Ang Qiao1, Hemin Zhou1
1State Key Laboratory of Silicate Materials for Architectures (Wuhan University of Technology), Wuhan 430070, China.
Chemical communications (Cambridge, England)
|September 19, 2023
概括
高密度无形阶段的双金属氧化伊米达酸框架 (Zn/Co-ZIF-4) 呈现玻璃过渡温度 (Tg) 不线性下降随着含量增加,揭示混合金属节点效应.
科学领域:
- 材料科学 材料科学 材料科学
- 化学 化学 化学
- 物理 物理学 物理
背景情况:
- 氧化模酸框架 (ZIFs) 是一种具有多种应用的金属有机框架 (MOFs) 类.
- 与其晶体对应物相比,ZIF的高密度无形 (HDA) 阶段表现出独特的特性.
- 了解无形MOF的玻璃过渡行为对于其材料设计和应用至关重要.
研究的目的:
- 为了制备双金属化物化物化物框架 (Zn/Co-ZIF-4) 的高密度无形相 (HDA).
- 为了研究等离体热容量 (Cp) 的温度依赖性,确定这些HDA的玻璃过渡温度 (Tg).
- 阐明混合金属组成对玻璃过渡行为和网络特性的影响.
主要方法:
- 合成双金属Zn/Co-ZIF-4 HDAs. 这是一个非常好的方法.
- 测量等离子热容量 (Cp) 作为温度的函数.
- 分析了玻璃过渡温度 (Tg) 和摩尔比率 (R = Co/(Co + Zn)) 之间的关系.
主要成果:
- 成功确定了 Zn/Co-ZIF-4 HDA 的 Tg.
- 随着摩尔比率R (Co/(Co + Zn)) 的增加,Tg非线性下降.
- 确定了一种混合金属节点效应,与配置自由和网络连接相关.
结论:
- 这项研究揭示了双金属ZIF-4HDAs在玻璃过渡中的显著混合金属节点效应.
- 配置自由和网络连接,受四面体对称的影响,在观察到的Tg行为中发挥关键作用.
- 这项研究为金属有机框架的玻璃过渡机制提供了宝贵的见解.
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