Protonation of Nitrogen-Containing Covalent Organic Frameworks for Enhanced Catalysis

Covalent organic frameworks (COFs) are a class of porous crystalline materials with ordered structures and tunable properties, which have been widely explored in catalysis, sensing, gas storage, and separation. Among various post-synthetic modifications, protonation emerges as a simple yet effective strategy to fine-tune the properties of nitrogen-containing COFs, thereby enhancing their catalytic performance. This concept article highlights the contribution of protonation on the mass transfer kinetics, charge distribution, photo-response, charge transfer, and other properties related to photocatalysis and electrocatalysis. The applications of protonated COFs are explored in catalytic processes including hydrogen evolution, CO₂ reduction, H₂O₂ synthesis, and singlet oxygen generation. We also emphasize the necessity of considering the protonation process when nitrogen-containing COFs are applied in acidic environments to accurately reveal the structure-activity relationship. By analyzing recent advancements in protonated COFs, this article underscores the potential and challenges of protonation as a powerful tool for advancing COF-based catalytic systems.