基于导电金属聚酞菁构造多元单原子催化剂的结构设计及电催化机制研究

The development of high-performance and low-cost single-atom electrocatalysts has become one of the crucial issues in the improvement of energy conversion and electrochemical application. One of the research hot topics is to unravel the scientific issues of the controlled preparation for structures and numbers of single-atom active sites and to obtain the multi-site single-atom electrocatalysts with high site density. In this proposal, we use the conductive metal polyphthalocyanines (C-MPPc) as the electrocatalytic molecules or precursors to prepare the multi-site single-atom electrocatalysts by supporting on carbon carriers (or not). Considering the strong coordination of the phthalocyanine ring and the high conductivity of the conjugated cross-linked structure, the design in this proposal is rational and effective. The proposal starts with the controllable synthesis of C-MPPc by selecting the central metals, crosslinkers and blocking agents to optimize the molecular structure. Then this proposal intends to study the carbon carriers and preparation processes to establish the controllable preparation of the multi-site single-atom electrocatalysts derived from C-MPPc. Finally, the oxygen reduction reaction (ORR) performance and mechanism of the as-prepared electrocatalysts will be investigated by electrochemical testing and theoretical calculations to provide informative conclusions (especially for the ligand effects, geometric effects and synergistic effects via multiple active sites) and to further improve ORR performances of multi-site single-atom catalysts derived from C-MPPc. The achievements will promote the development of single-atom catalysts for various electrochemical devices.

实现高性能单原子氧气还原反应电催化剂的设计与可控制备具有深远的科学意义和重要的应用价值。目前相关研究热点之一是通过单原子位点结构和数目的调控机制等基本科学问题的揭示，以实现具有高位点密度的多元单原子催化剂的可控制备和高性能化。本项目利用酞菁环的强配位作用和共轭交联结构的高导电性，通过探讨多组分导电金属聚酞菁的结构设计，研究载体选择以及制备工艺，制备具有高位点密度多元单原子催化剂，以实现高体积比活性催化材料的设计要求。通过物性表征、电化学测试和分子模拟相结合的方式，研究催化表面状态及性能、活性位点组成及结构、载体效应等，考察单原子位点的存在形式和形成过程。通过进一步强化多元单原子催化体系下的配体效应、几何效应和协同效应，最终建立高位点密度多元单原子催化剂制备、结构和性能的构效关系，为实现高性能单原子催化剂在电催化领域中的应用和性能调控提供理论依据。

高性能、低成本单原子电催化剂的研究是目前最重要的研究方向之一，但目前的单原子催化剂仍然存在活性位点密度低、本征活性不高等问题，导致其质量/体积比活性较低，在实际能源器件中的应用不尽如人意。基于此，本项目从导电金属聚酞菁的组成结构和尺寸分散的设计入手，制备具有高位点密度的多元单原子催化剂，研究强化多元催化体系的增强机制，探索表面反应性、催化活性以及稳定性的影响机制，揭示多元单原子位点催化氧还原反应途径，最终建立多元单原子催化剂制备、结构和性能的构效关系，为高性能单原子催化材料设计和性能调控提供理论依据，同时扩展了单原子催化剂在电催化领域中的应用。项目执行期间，项目负责人以第一/通讯作者在J. Am. Chem. Soc., Angew. Chem., Int. Ed., Adv. Mater., Chem. Soc. Rev.等高水平期刊发表相关SCI论文18篇，申请发明专利2项（授权1项）。