Constructing Polyamine-Rich Zr-Based Metal−Organic Frameworks via Linker-Vacancy Engineering for Carbon Capture

Porous solid adsorbents are a promising class of materials for carbon dioxide (CO2) capture owing to their structural tunability, high surface area, and low regeneration energies. Amine-functionalized sorbents offer strong CO2 affinity under humid and low-concentration conditions. However, grafting and impregnation often lead to amine loss and poor durability, and covalent polyamine incorporation typically requires complex multistep syntheses with limited scalability. Herein, we present a defect-driven polyamine growth strategy in zirconium-based metal−organic frameworks (MOFs) that enables uniform and dense polyamine incorporation. Selective linker-vacancy formation in tetracarboxylate-linker-based Zr-MOFs generates abundant coordinatively unsaturated Zr sites that initiate efficient in-pore polyamine polymerization while preserving framework stability. The resulting polyamine-rich MOFs display markedly enhanced low-pressure CO2 adsorption, and the best-performing material exhibits a 1881-fold increase in uptake at 0.4 mbar compared to the pristine framework. This simple and broadly applicable approach provides a powerful route for constructing polyamine-functionalized MOFs for advanced applications in energy and environmental technologies.