Alkoxy Side Chain Engineering in Metal‐Free Covalent Organic Frameworks for Efficient Oxygen Reduction
Abstract
AbstractMetal‐free covalent organic frameworks (COFs) gain significant attention as catalysts for the oxygen reduction reaction (ORR), a key process in energy conversion technologies like fuel cells and metal–air batteries. While substantial efforts are devoted to unravelling the mechanisms, by which heteroatom‐containing building blocks in linkers, vertices, and linkages, enhance catalytic activity and selectivity, the potential of side‐chain engineering to modulate pore wall surfaces and optimize the catalytic environment remains largely underexplored. This study investigates the role of alkoxy side chains in modulating the properties of COFs to enhance ORR performance. The synthesized COFs have adjustable pore surfaces, integrating triazine rings and alkoxy groups to enhance channel hydrophilicity by modulating interactions with water molecules. Moreover, the alkoxy side chains act as electron donors through p–π conjugation, creating active and tuneable electronic sites, further enhancing hydrophilicity and facilitating efficient catalytic cycles. Notably, COFs with longer alkoxy side chains exhibit superior ORR activity, with a half‐wave potential of 0.77 V, surpassing previously reported metal‐free COFs. Theoretical calculations suggest that this enhancement is because of the stronger binding affinity of water molecules and *OOH intermediates to the carbon atoms adjacent to the alkoxy side chains.
Article Details
Authors (13)
Zhongping Li
Department of Energy and Chemical Engineering/Center for Dimension-Controllable Organic Frameworks, Ulsan National Institute of Science and Technology, 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 44919, Republic of Korea
Zhaoying Wang
Key Laboratory of Mass Spectrometry Imaging and Metabolomics (Minzu University of China), State Ethnic Affairs Commission, Center for Imaging and Systems Biology, College of Life and Environmental Sciences
Songlin Zhao
School of Energy & Chemical Engineering Ulsan National Institute of Science and Technology (UNIST) Ulsan 44919 Republic of Korea
Jeong‐Min Seo
Department of Energy and Chemical Engineering/Center for Dimension‐Controllable Organic Frameworks Ulsan National Institute of Science and Technology (UNIST) Ulsan 44919 Republic of Korea
Changqing Li
School of Energy and Chemical Engineering/Center for Dimension-Controllable Organic Frameworks
Yucheng Jin
Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, Department of Chemistry and Chemical Engineering, School of Chemistry and Biological Engineering
Siliu Lyu
Hubei Key Laboratory of Automotive Power Train and Electronics School of Automotive Engineering Hubei University of Automotive Technology Shiyan 442002 China
Jian Li
Feng Tang
State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, No.555 Zuchongzhi Rd, Pudong, Shanghai 201203, China
Won‐Yeong Kim
Department of Chemical and Biomolecular Engineering Yonsei University Seoul Republic of Korea
Zonghoon Lee
Sang‐Yong Lee
Department of Chemical and Biomolecular Engineering Yonsei University Seoul 03722 Republic of Korea
Jong‐Beom Baek
Department of Energy and Chemical Engineering Center For Dimension‐Controllable Organic Frameworks Ulsan National Institute of Science and Technology Ulsan South Korea