基于互穿框架的调控及功能型混合配体高质子传导MOFs的合成与研究

Proton Conduction Metal-Organic Frameworks (PC-MOFs) has great potential values for the exploitation and applications of fuel cells. Yet, most reports show that the proton conductivity of PC-MOFs has been normally far lower than that of classical proton conduction materials, such as Nafion. Therefore, it is a challenging and significant task to design and synthesize MOFs with high proton conductivities. In this project, delicate control to the interpenetrated frameworks of MOFs is mainly used to induce or improve their proton conduction. We plan to design and synthesize interpenetrated proton conduction MOFs (IPC-MOFs) with high proton conductivity, using rare-earth and transition metal ions and functional mixed ligands of aromatic ligands modified with bronsted acid groups and linear pyridine derivatives co-ligands, by means of hydrothermal or solvothermal conditions etc. Reaction conditions to synthesize IPC-MOFs will be well explored by changing influential factors such as temperatures, solvents, and so on. We also intend to reveal the relationship between the interpenetrated frameworks and proton conduction property, followed by studying the proton conduction mechanism, and the further the applications of IPC-MOFs. Through this project, we expect to obtain proton conduction IPC-MOFs materials which are comparable to or ideally more excellent than Nafion, better to illustrate the proton conduction mechanism at a molecular level, and to lay the foundation for the applications as new-generation fuel cells.

质子传导金属-有机框架材料（PC-MOFs），虽然在燃料电池的开发应用方面存在巨大的潜在价值，但目前研究表明其质子传导率往往比经典质子传导材料Nafion低得多，因此设计合成具有高质子传导率的MOFs是既有挑战又有现实意义的课题。本项目拟通过对MOFs互穿框架结构的精细调控，来诱发或提高其质子传导性能。核心思路是选用由质子酸芳香类主配体及线型吡啶类辅助配体组合成的功能型混合配体，采用水热、溶剂热等方法，与稀土或过渡金属离子自组装，构建具有互穿框架、高质子传导率的MOFs。通过优化反应温度、溶剂等实验参数摸索互穿框架PC-MOFs的制备条件；重点考察互穿框架与质子传导性能的构效关系；深入研究其质子传导机理，进而探索其应用性能。通过本项目的实施，有望使MOFs成为与Nafion相近甚至更优越的质子传导材料，更好地从分子水平上去研究质子传导机理，为新一代燃料电池的研究开发提供理论依据和实践基础。

在本项目执行期间，我们围绕课题内容，积极开展研究工作，具体如下：1. 选择磺酸或膦酸质子酸基团修饰的芳香类主配体，及线状吡啶类辅助配体组成功能型混合配体（其中主配体主要负责提供质子载体并形成质子传输路径；而分子尺寸较长的线状辅助配体则主要用来诱导构建互穿式框架结构），与稀土金属离子（La3+、Ce3+、Pr3+、Nd3+等）或过渡金属离子（Co2+、Ni2+、Cu2+、Zn2+、Cd2+等）配位，设计合成了多例具有高质子传导率的IPC-MOFs；2. 利用后合成方法，对所得IPC-MOFs进行修饰，如对水合IPC-MOFs修饰亲水性更强的聚合物等；对非水合IPC-MOFs则负载具有高沸点不易挥发的分子，如咪唑、三氮唑等。使得水合型在低相对湿度条件下仍具有高质子传导性能；非水合型在尽可能高的温度（>100°C）下具有高质子传导率（>=0.13S cm-1）；3. 选择质子传导率高的优质IPC-MOFs质子传导材料，初步开展了其在燃料电池等方面的应用性能探索。通过本项目的实施为新一代燃料电池的研究和开发提供了一定的理论依据和实践基础。