金属有机骨架复合薄膜材料电荷转移机理的研究及其污染物分子的电化学检测

Host–guest interaction and charge transfer mechanism between metal organic frameworks (MOFs) and redox-active species are intensely important in oxidation-reduction chemistry of MOFs. Currently, there are a limited number of studies reported on the host–guest and charge transfer interactions of redox-active species with MOFs. Furthermore, the limited understanding on the interactions of redox-active molecules in a specific MOF and a selected molecule in random MOFs, makes it difficult to compare their results and draw a comprehensive conclusion. In this project, two iso-structural types of MOF films are synthesized systematically in the following two strategies: changing the metal ions with the same organic ligands, and selecting various organic ligands functionalized with different functional groups while keeping the metal ion constant in order to retain the same crystalline MOF films. For detailed investigation, direct characterization tools of adsorption, vibrational spectrum (infrared spectroscopy and Raman spectroscopy) and solid state electrochemistry will be employed. Solid state spectro-electrochemical techniques based on IR and Raman spectroscopies will provide details on the host–guest and charge transfer interactions of redox-active species and MOF films by monitoring the vibration modes and redox-accessible states when the redox-active species contact with MOF films. The underling rules of host–guest and charge transfer interactions between redox-active species and MOF films will be clarify and summarized, which will provide us guidance on the detection of the environmentally hazardous substances using the redox-active species-loaded MOF composite film electrodes as electrochemical sensors as well as the elucidation of their sensing mechanism. The results based on these future studies will provide theoretical and practical basis for realizing targeted design and adjustment of MOFs materials between their structure and function.

金属有机框架材料（MOFs）与氧化还原活性分子间的相互作用及其电荷转移机理一直是MOFs氧化还原化学领域的研究重点；但目前相关工作的报道数量有限，且这些工作多集中于多种氧化还原活性分子与一种选定MOF或一种氧化还原活性分子与不同MOFs相互作用，这些MOFs具有不同的金属离子和有机配体，难以总结出一般性的电荷转移规律。基于以上问题，本项目拟合成具有相同配体不同金属中心和相同金属中心不同功能化的配体的两类同构MOFs薄膜，利用吸附、振动光谱和固体电化学技术直接研究嵌入每个骨架孔结构内部的金属中心或功能化有机配体与负载的氧化还原活性分子间的相互作用，进而系统探究其电荷转移规律，并将此规律用于指导负载氧化还原活性分子的MOFs复合薄膜电极的污染物分子的电化学检测和传感机理研究，为实现MOFs材料结构与功能的定向设计和调控提供理论和实验依据。

金属有机框架材料(MOF)作为一种新颖的纳米孔金属配合物材料，其氧化还原化学的主要挑战是开发具有氧化还原活性的新材料并系统地研究其电荷转移与传输的机理。但传统方法构建的MOF材料往往具有低的氧化还原活性和低的导电性，限制了MOF在分子电化学传感领域的应用。本项目利用π-π堆积、共价键合和交联作用设计并合成系列MOF基复合材料，构建了以还原性氧化石墨烯、聚噻吩和Mxene为导电基底，ZIF-C、HZIF、Ni/Co-MOF等金属有机框架材料为氧化还原体的电化学检测平台。主要研究工作包括：（1）一步搅拌法制备2D/2D/2D ZIF-C/g-C3N4/rGO三元异质结构和羧基功能化的还原氧化石墨烯(CFG)上原位成核形成多金属氧酸盐金属-有机骨架(NENU-3)，并用于水合肼的高效检测；（2）以DAAQ-TFP多孔有机框架为主体材料，利用主客体相互作用同时移除和电化学检测水合肼；（3）采用微波辅助、滴涂和气相沉积等方法在碳布电极上构建杂化沸石型咪唑盐骨架（HZIF）与导电聚合物（3, 4-乙烯二氧噻吩）的复合物（HZIF-Mo/PEDOT），并用于羟胺的快速检测。（4）利用三聚氯氰和三氯氰胺之间的缩合反应制备-NH-连接的共价有机骨架(NUF)，与TiO2/Ti3C2超声形成TiO2/TiCT/NUF复合材料，用于多巴胺和尿酸的同时检测。（5）利用超声法制备Ni/Co-MOF纳米片与Ti3C2杂化物，形成Ni/Co-MOF/Ti3C2复合材料，实现多巴胺、尿酸和对乙酰氨基酚分子的同时检测。（6）利用浸渍法将Bi离子负载于MIL-101(Cr)中后涂布到碳布载体上，在电还原的条件下获得Bi/MIL-101(Cr)/CC。利用差分脉冲阳极溶出伏安技术(DPASV)实现对Pb2+和Cd2+的同时检测。本项目的研究可望建立新型MOF基氧化还原活性材料的制备方法和污染物分子和疾病分子的高灵敏度检测方法，为MOF及传感材料的制备、优选和应用提供新思路，为构建高效的电子转移体系提供有益借鉴。