Zhang Meng-Di, Si Duan-Hui, Yi Jun-Dong, Zhao Shao-Shuai, Huang Yuan-Biao, Cao Rong
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002, China.
College of Chemistry and Materials Science, Fujian Normal University, Fuzhou, 350007, China.
Small. 2020 Dec;16(52):e2005254. doi: 10.1002/smll.202005254. Epub 2020 Dec 1.
The electroreduction of CO to value-added chemicals such as CO is a promising approach to realize carbon-neutral energy cycle, but still remains big challenge including low current density. Covalent organic frameworks (COFs) with abundant accessible active single-sites can offer a bridge between homogeneous and heterogeneous electrocatalysis, but the low electrical conductivity limits their application for CO electroreduction reaction (CO RR). Here, a 2D conductive Ni-phthalocyanine-based COF, named NiPc-COF, is synthesized by condensation of 2,3,9,10,16,17,23,24-octa-aminophthalocyaninato Ni(II) and tert-butylpyrene-tetraone for highly efficient CO RR. Due to its highly intrinsic conductivity and accessible active sites, the robust conductive 2D NiPc-COF nanosheets exhibit very high CO selectivity (>93%) in a wide range of the applied potentials of -0.6 to -1.1 V versus the reversible hydrogen electrode (RHE) and large partial current density of 35 mA cm at -1.1 V versus RHE in aqueous solution that surpasses all the conventional COF electrocatalysts. The robust NiPc-COF that is bridged by covalent pyrazine linkage can maintain its CO RR activity for 10 h. This work presents the implementation of the conductive COF nanosheets for CO RR and provides a strategy to enhance energy conversion efficiency in electrocatalysis.
将CO电还原为增值化学品（如CO）是实现碳中性能源循环的一种有前景的方法，但仍然面临包括低电流密度在内的巨大挑战。具有丰富可及活性单位点的共价有机框架（COF）可以在均相和异相电催化之间架起一座桥梁，但低电导率限制了它们在CO电还原反应（CO RR）中的应用。在此，通过2,3,9,10,16,17,23,24-八氨基酞菁镍（II）与叔丁基芘四酮缩合合成了一种二维导电镍酞菁基COF，命名为NiPc-COF，用于高效CO RR。由于其高度的本征导电性和可及活性位点，坚固的导电二维NiPc-COF纳米片在相对于可逆氢电极（RHE）为-0.6至-1.1 V的广泛应用电位范围内表现出非常高的CO选择性（>93%），并且在水溶液中相对于RHE为-1.1 V时具有35 mA cm的大的分电流密度，超过了所有传统的COF电催化剂。由共价吡嗪键连接的坚固的NiPc-COF可以保持其CO RR活性10小时。这项工作展示了导电COF纳米片在CO RR中的应用，并提供了一种提高电催化中能量转换效率的策略。
