2025-04-21 中国科学院（CAS）
＜関連情報＞
- https://english.cas.cn/newsroom/research_news/chem/202504/t20250421_1041629.shtml
- https://www.pnas.org/doi/10.1073/pnas.2419434122
機能化MOFナノシートにおけるその場生成水素結合微小環境によるCO2電気還元反応の促進 In situ generated hydrogen-bonding microenvironment in functionalized MOF nanosheets for enhanced CO2 electroreduction
Ge Yang, Jiajia Huang, Weizhi Gu, +7 , and Hai-Long Jiang
Proceedings of the National Academy of Sciences Published:April 10, 2025
DOI:https://doi.org/10.1073/pnas.2419434122
Significance
The microenvironment around catalytic sites, created by the precisely arranged amino acid residues, has been proved to play significant roles in enzyme catalysis. Inspired by this, the construction of biomimetic microenvironment is a promising way to improve catalytic performance of artificial catalysts while this remains a great challenge. Our study presents the precise modulation of hydrogen-bonding microenvironment in functionalized metal-organic framework nanosheets by the in situ transformation of pyridinic units under working potentials. The in situ generated hydrogen-bonding microenvironment around catalytically active Co(salen) units facilitates the stabilization of *COOH intermediate and therefore greatly enhances CO2 electroreduction. This unambiguously demonstrates the significance of microenvironment around catalytic sites and unveils in situ dynamic transformation mechanism during electrocatalysis.
Abstract
The microenvironment around catalytic sites plays crucial roles in enzymatic catalysis while its precise control in heterogeneous catalysts remains challenging. Herein, the coordinatively unsaturated metal nodes of Hf-based metal-organic framework nanosheets are simultaneously codecorated with catalytically active Co(salen) units and adjacent pyridyl-substituted alkyl carboxylic acids via a post modification route. By varying pyridyl-substituted alkyl carboxylic acids, the spatial positioning of the N atom in pyridine group relative to adjacent Co(salen) can be precisely controlled. Notably, the 3-(pyridin-4-yl)propionic acid, with para-position pyridine N atom, maximally improves the electrocatalytic CO2 reduction performance of Co(salen) unit, far superior to other counterparts. Mechanism investigations reveal that the pyridine unit of 3-(pyridin-4-yl)propionic acid is optimally positioned relative to Co(salen) and undergoes in situ reduction to pyridinyl radical under working potentials. This greatly facilitates the stabilization of *COOH intermediate via hydrogen-bonding interaction, lowering the formation energy barrier of *COOH and therefore boosting CO2 electroreduction.
