Triazole-Based Metal-Organic Frameworks for CO₂ Capture

Metal-organic frameworks (MOFs) based on triazole have attracted considerable interest as promising porous materials for CO₂ capture due to their high surface area, ultramicroporosity, and excellent thermal and chemical stability. Nitrogen-rich triazole ligands contain abundant Lewis basic sites that promote CO₂ adsorption via dipole-quadrupole interactions, hydrogen bonding and cooperative interactions with open metal sites. The present review discusses recent developments in the synthesis of triazole-based MOFs, with special emphasis on the relation between structural features and CO₂ adsorption performance. The paper reviews different synthetic routes such as solvothermal, hydrothermal, mechanochemical and post-synthetic modification methods and their impact on crystallinity, porosity and scalability. The roles of metal centres, pore confinement and linker functionalization in tuning CO₂ uptake, selectivity and adsorption energetics are highlighted. Moreover, the mixed-linker strategies and defect engineering are explored to illustrate the use of the synergistic effect of nitrogen-rich sites and metal nodes for the improvement of the adsorption performance. Still, a number of challenges remain such as achieving an optimal balance between adsorption strength and regenerability, increasing stability in humid and realistic flue-gas conditions, and the development of scalable and sustainable synthesis routes. In summary, triazole-based MOFs provide a versatile platform for the design of high-performance CO₂ adsorbents by combining structural robustness with chemically active, nitrogen-rich adsorption environments.