Li Bo-Quan, Zhao Chang-Xin, Chen Shuangming, Liu Jia-Ning, Chen Xiao, Song Li, Zhang Qiang
Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, P. R. China.
National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui, 230029, P. R. China.
Adv Mater. 2019 May;31(19):e1900592. doi: 10.1002/adma.201900592. Epub 2019 Mar 25.
High-performance bifunctional oxygen electrocatalysis constitutes the key technique for the widespread application of clean and sustainable energy through electrochemical devices such as rechargeable Zn-air batteries. Single-atom electrocatalysts with maximum atom efficiency are highly considered as an alternative of the present noble-metal-based electrocatalysts. However, the fabrication of transition metal single-atoms is very challenging, requiring extensive attempts of precursors with novel design principles. Herein, an all-covalently constructed cobalt-coordinated framework porphyrin with graphene hybridization is innovatively designed and prepared as the pyrolysis precursor to fabricate single-atom Co-N -C electrocatalysts. Excellent electrochemical performances are realized for both bifunctional oxygen electrocatalysis and rechargeable Zn-air batteries with regard to reduced overpotentials, improved kinetics, and prolonged cycling stability comparable with noble-metal-based electrocatalysts. Design principles from multiple scales are proposed and rationalized with detailed mechanism investigation. This work not only provides a novel precursor for the fabrication of high-performance single-atom electrocatalysts, but also inspires further attempts to develop advanced materials and emerging applications.
高性能双功能氧电催化是通过可充电锌空气电池等电化学装置实现清洁和可持续能源广泛应用的关键技术。具有最大原子效率的单原子电催化剂被高度视为当前基于贵金属的电催化剂的替代品。然而，过渡金属单原子的制备极具挑战性，需要对具有新颖设计原理的前驱体进行大量尝试。在此，创新性地设计并制备了一种与石墨烯杂化的全共价构建的钴配位框架卟啉，作为热解前驱体来制备单原子Co-N-C电催化剂。在双功能氧电催化和可充电锌空气电池方面均实现了优异的电化学性能，包括降低过电位、改善动力学以及与基于贵金属的电催化剂相当的延长循环稳定性。提出了多尺度的设计原理，并通过详细的机理研究进行了合理化。这项工作不仅为制备高性能单原子电催化剂提供了一种新型前驱体，还激发了进一步开发先进材料和新兴应用的尝试。
