多金属团簇MOFs可控热解及衍生物的电化学催化性能研究

Owing to the monodispersed metal centers, structural diversities and the high specific surface area, metal-organic frameworks (MOFs) are an ideal class of precursors and templates for synthesizing nanomaterials. Recently, there are plenty of works utilizing monometallic MOFs to synthesize electrocatalysts. However, the performances of these materials are less than satisfactory. Furthermore, as for the mixed-metal electrocatalysts, which generally perform higher electrocatalytic activities compared to analogues with monometallic composition, the relevant research is relatively insufficient and the relationship between their structure and catalytic activity is still under debate. In this project, at first, through designing the secondary building units of MOFs, we plan to synthesize a series of novel MOFs with desirable mixed-metal clusters that disperse homogeneously in three-dimensional structures. Then, controlled conversion of mixed-metal MOFs to corresponding mixed-metal derivatives without metal aggregation and skeleton collapse is to be achieved via incorporating polymers that contain heteroatoms (N, P, S, O, etc.) into the obtained MOFs and anchoring the metal centers in MOFs during the pyrolysis. Afterwards, the obtained derivatives will be applied in different electrochemical catalysis reactions according to their various structures and chemical compositions. On top of that, the contribution of this project may cover but is not limited to the following aspects: (1) clarifying the influences on pyrolysis of different metal elements in MOFs as well as the heteroatoms in polymers; (2) establishing relationships among secondary building units, three-dimensional reticular structures and the corresponding derivatives, which helps to optimize the further synthesis of novel nanomaterials; (3) elucidating the mechanism of synergistic effect and the structure-activity relationship in mixed-metal nanomaterials; (4) promoting the future development in the fields of MOFs, nanomaterials as well as electrocatalysis.

金属有机框架材料（MOFs）因金属单分散、结构丰富多样、比表面积高，是理想的制备纳米材料的前驱体/模板。目前已有大量研究通过MOFs制备单一金属组成的电化学催化剂，不过这些单金属催化剂的性能仍有较大提升空间，而且目前对多金属体系的催化剂研究较少，其中的构效关系及协同作用机理也并不明确。本项目拟通过对次级结构单元的设计，开发一系列新型多金属团簇MOFs，以得到三维空间里分布均匀的多金属团簇；然后在孔内引入含有杂原子的聚合物，固定金属位点，抑制团聚，防止坍塌，辅助MOFs热解转化，以实现可控热解；最终将相应的多金属体系衍生材料应用于电化学催化反应中，以实现高效催化转化。在此基础上拟明确MOFs中不同金属和引入的杂原子对热解过程的影响，建立次级结构单元-三维网状结构-衍生纳米材料之间的有机联系，并进一步指导衍生材料的优化，阐明多金属纳米材料的构效关系和金属协同作用机理，为相关领域发展提供参考。

金属有机框架材料（MOFs）因金属单分散、结构丰富多样、比表面积高，是理想的制备纳米材料的前驱体/模板。本项目设计合成了不同结构的双金属和三金属MOFs，调控了MOFs的热分解转化过程，实现了MOFs的可控热解，并且研究了热解得到的衍生纳米材料的电化学催化性能，还将研究对象拓展到共价有机框架材料中。具体研究成果如下：.1) 设计合成了Fe/Zn双金属MOF，并且借助三氮唑配体受热分解会产生大量气体的特性以及含氯配体的混配结构，热解后MOF中的金属节点转化为FeN4Cl1单原子位点，有机配体转化为具有丰富梯级孔的氮掺杂碳；研究了其对氧还原反应的高催化活性、在锌-空气电池中的应用以及反应机理。.2) 设计合成了Mn/Co/Ni三金属MOF，并且通过微波辅助溶剂热法，控制其形貌，进而通过热解将其转化为具有空心结构的正十二面体衍生物；研究了其对氧还原反应的高催化活性和在锌-空气电池中的应用。.3) 通过改变MOF配体中的氮含量，有效调控MOF热分解过程中的氧气分压，制备出一系列含有不同氧空位浓度的IrOx/CeO2团簇催化剂；研究了其对酸性氧析出反应的高活性以及反应机理。.4) 拓宽研究体系至共价有机框架（COFs），研究Pt负载的COF热解过程，得到了对氧气还原反应具有高催化活性和稳定性的铂基催化剂。.5) 梳理总结了通过可控热分解MOFs制备氧还原单原子催化剂的不同方法和研究进展，撰写综述。.6) 梳理总结了在MOFs及MOFs热解衍生物中引入贵金属纳米颗粒的不同方法和研究进展，撰写综述。.项目成果总结为6篇SCI检索期刊论文。研究成果可望应用于质子交换膜燃料电池、锌-空气电池等新型储能器件，同时为新能源材料的设计提供理论支撑。.项目负责人参加国内学术会议3次，并做口头报告1次。培养硕士1名，联合培养硕士1名、博士2名。.