南京师范大学兰亚乾团队报道了在基于卟啉的共价有机框架中加入CO₂电还原辅助物以实现整体形态调节和性能提升。相关研究成果于2021年11月21日发表于国际顶尖学术期刊《德国应用化学》。

为了开发高效CO₂电还原中的共价有机框架，迫切需要能够同时调节形态和提高电还原性能的策略。

该文中，研究人员选择了一种功能化剥离剂，同时将大块COFs改性并剥离成功能性纳米片，并研究其CO₂电还原性能。所获得的具有大尺寸（~1.0μm）、超薄（~3.8 nm）形貌的纳米片（Cu-Tph-COF-Dct）能够在-0.9 V的大电流密度（-220.0 mA cm^-2）下实现优异的FECH4（~80%）（几乎是裸COFs的两倍）。

DFT计算表明，性能提高是由于固定化功能化剥落剂（Dct组）集成的氨基和三嗪基团可增强CO₂吸收/活化，稳定中间产物并富集铜活性中心周围的CO浓度。模块化组装用于CO₂电还原的Dct功能化COFs催化剂的点对点功能化策略，将为开发COFs作为高效CO₂RR电催化剂开辟有吸引力的可能性。

附：英文原文

Title: Imparting CO2 Electroreduction Auxiliary for Integrated Morphology Tuning and Performance Boosting in a Porphyrin-based Covalent Organic Framework

Author: Ya-Qian Lan, Yi-Rong Wang, Hui-Min Ding, Xiao-Yu Ma, Ming Liu, Yi-Lu Yang, Yifa Chen, Shun-Li Li

Issue&Volume: 2021-11-21

Abstract: Strategies that enable simultaneous morphology-tuning and electroreduction performance boosting are much desired for the exploration of covalent organic frameworks in efficient CO2 electroreduciton. Herein, a kind of functionalizing exfoliation agent has been selected to simultaneously modify and exfoliate bulk COFs into functional nanosheets and investigate their CO2 electroreduction performance. The obtained nanosheets (Cu-Tph-COF-Dct) with large-scale (~1.0 μm) and ultrathin (~3.8 nm) morphology enable a superior FECH4 (~80%) (almost doubly enhanced than bare COF) with large current-density (-220.0 mA cm-2) at -0.9 V. The boosted performance can be ascribed to the immobilized functionalizing exfoliation agent (Dct groups) with integrated amino and triazine groups that strengthen CO2 absorption/activation, stabilize intermediates and enrich the CO concentration around the Cu active sites as revealed by DFT calculations. The point-to-point functionalization strategy for modularly assembling Dct-functionalized COF catalyst for CO2 electroreduction will open up the attractive possibility of developing COFs as efficient CO2RR electrocatalysts.

DOI: 10.1002/anie.202114648

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202114648