Fe-金属有机框架玻璃的形成过程与机理  

Formation Mechanism of a Fe-based Metal-Organic Frameworks Glass

作　　者：刘鑫宇 郭超慧 陶海征[1] 乔昂 LIU Xinyu;GUO Chaohui;TAO Haizheng;QIAO Ang(State Key Laboratory of Silicate Materials for Architectures,Wuhan University of Technology,Wuhan 430070,China;Wuhan University of Technology Advanced Engineering Technology Research Institute of Zhongshan City,Zhongshan 528400,Guangdong,China)

机构地区：[1]武汉理工大学硅酸盐建筑材料国家重点实验室,武汉430070 [2]中山市武汉理工大学先进工程技术研究院,广东中山528400

出　　处：《硅酸盐学报》2024年第8期2553-2558,共6页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金(22175135);广东省基础与应用基础研究基金自然科学基金项目(2022A1515010312)。

摘　　要：不同的中心金属离子能够赋予金属有机框架材料(MOFs)不同的性能,众多Fe基MOF材料具有优异的电、磁性能。但由于Fe元素存在变价,且Fe—N配位键难以形成,可熔融成玻Fe-MOF材料鲜有报道。使用无溶剂法成功制备Fe_(3)(C_(3)H_(2)N_(2))_6(C_(3)H_(4)N_(2))_(2)晶体,命名为FCIR,即Fe-MOF晶体,并且利用熔融淬冷法制成了Fe-MOF玻璃,并探究该Fe-MOF晶体在加热过程中的形态和结构演变,以及其玻璃态形成的机理。结果表明:相较于以Zn为中心离子的可熔融MOF材料,Fe离子对晶体加热过程中的熔融过程和结构演变会产生较大影响;FCIR晶体熔融淬冷后发生近程序结构变化,即由晶态时Fe离子与咪唑的6配位八面体脱去2个单配位咪唑转变为玻璃态的4配位四面体。Introduction Metal-organic frameworks(MOFs)exhibit excellent tunability in structure,primarily due to the mutual substitution and doping of central ions and organic ligands.Changes in central ions and organic ligands could impact their glass-forming stability,pore size,catalytic ability,and other physicochemical properties.For example,the MIL-100 metal-organic framework materials,centered around chromium ions,exhibits high stability and catalytic activity in oxidation reactions.However,replacing chromium ions with aluminum ions will lead to decreased stability and catalytic activity in oxidation reactions.Therefore,exploring the mutual combinations of different metal ions and organic ligands is crucial for developing new MOFs.Fe-MOF,characterized by highly controllable pore structure,excellent catalytic performance,and magnetism,is widely applied in the fields of gas adsorption and separation,catalysis,drug delivery,and environmental protection.However,the activity of Fe ions induces a low thermal stability,which consequently leads to the decomposition of most Fe-MOF crystals prior to melting.This impedes the glass transition process through melt-quenching.In this study,a solvent-free method was utilized to prepare a Fe-MOF crystal,which was subsequently transformed into glass state via melt-quenching.The morphological and structural evolution of this Fe-MOF during heating,as well as the mechanism underlying its glass transition,were thoroughly investigated.Methods In a meticulously controlled environment within a glove box featuring extremely low levels of oxygen and water content(oxygen content≤0.282 mg·m^(–3),water content≤0.3 mg·L^(–1)),the mass of 1.86 g ferrocene and 1.362 g imidazole were weighed,blended together within a polytetrafluoroethylene container and sealed within a sturdy steel outer casing.Subsequently,the reaction vessel was transferred to a high-temperature blast drying oven,following by a controlled reaction process at 150℃for 96 h.After the reaction,the product was washed with di

关 键 词：金属有机框架 玻璃形成 熔融 结构变化 

分 类 号：TQ171.1[化学工程—玻璃工业]