具有高密度活性位点和框架结构限域的氧还原电催化剂的可控制备与性能研究

由于金属有机框架（MOF）/共价有机框架（COF）材料结构设计性与裁剪性，近年来被广泛作为前驱体，通过掺杂适量过渡金属再经高温碳化来制备M-N/C非贵金属氧还原催化剂。但由于高温过程带来了结构的不可控性与不可预测性，最终产物的催化性能难以控制，因此，建立MOF/COF前驱体与最终产物催化剂性能的直接关联关系是研究的关键。本项目拟在多尺度模型化的理论指导下，设计和筛选孔结构与分子大小相匹配的主体MOF/COF 材料以及具有潜在活性位点的有机小分子客体，开展主客体型前驱体及高活性位点氧还原催化剂的可控合成。从原子、分子层面探明具有优异催化性能的氧还原活性位点，反向剖析制备催化剂所选用主客体类型及比例等因素，强化在结构导向性能的体系下，实现高活性非贵金属氧还原催化剂的可控制备，开辟由前驱体结构直接推演碳化样品性能的氧还原催化剂的制备新技术，为突破高效非贵金属基氧还原催化剂的大规模制备提供新方案。

Recently, metal-organic frameworks (MOF)/covalent organic frameworks (COF) were widely employed as precursors for preparing oxygen reduction electrocatalysts due to rich element choices and tunable structures. However, owing to the poor conductive properties of MOF/COF, their non-conductive conjugated structures or enhanced π conjugation by pyrolysis are essential for the electrocatalytic activity, which may induce undesirable structure changes and even destruct the fine structures, resulting in uncertain performance of electrocatalysis. Therefore, it is very important but remains challenging to study the relationship between the MOF/COF precursors and the final electrocatalysts to establish an approach to directly synthesize the desired electrocatalysts from the designed MOF/COF precursors. The project plans to design and screen highly active MOF/COF-based electrocatalysts by tuning porous structure of MOF/COF precursors and guests with appropriate molecular size under the guide of multiscale model theory. By exploring the relationship between the electrocatalytic performance and structures of the MOF/COF precursors in the molecular and atomic dimensions, we are trying to find a simple method to precisely synthesize highly efficient non-precious metal-based oxygen reduction electrocatalysts. This proposed approach will open a window for large-scale synthesis of highly efficient non-precious electrocatalysts with high-density active sites in well-defined atomic distribution, which is highly desired for the fuel cell and metal-air batteries.