An, Hong-Eun Kim, Wan-Tae Shin, Dong Yun Park, SeJin Yoon, Eunki Kim, Dae Won Hong, Chang Seop Park, Soohyung Oh, Hyunchul Lee, Jung-Hoon Jeong, Sohee 2025-09-01T15:00:06Z 2025-09-01T15:00:06Z 2025-09-01 2025-06 1385-8947 https://pubs.kist.re.kr/handle/201004/153093 One of the essential properties required for the practical application of metal？organic frameworks (MOFs) as gas storage materials is high water stability. In this study, we investigate the origin of improved water stability through thermal treatment in V3(PET), a MOF containing hexatopic peripherally extended triptycene (H6PET) ligands, which show promise for hydrogen storage. While V3(PET) should be water-stable due to strong metal (hard acid, V3+)-ligand (hard base, carboxylate group) bonds, our experimental and theoretical findings reveal that the presence of dangling ligand―defects caused by metal-modulator (acetate) bonds― reduces its water stability. Our first-principles density functional theory (DFT) calculations show that the defect formation energy for V3(PET) with dangling ligands (+1.96 eV) is significantly lower than that for V3(PET) without them (+6.34 eV), making it more vulnerable to humidity. By removing acetate and restoring the original metal？ligand bonds, we significantly enhance the water stability of V3(PET). Additionally, thermally treated V3(PET) retains about 95 % of its hydrogen storage performance even after 7 days in 60 % relative humidity and maintains high mechanical stability over 200 hydrogen storage cycles. English Elsevier BV Improved water stability by thermal treatment of hexatopic ligand-based metal-organic frameworks for hydrogen storage Article 10.1016/j.cej.2025.163083 1 Chemical Engineering Journal, v.513 Chemical Engineering Journal 513 N scie scopus 001685918600001 Engineering, Environmental Engineering, Chemical Engineering Article MOISTURE-RESISTANT STRUCTURAL DEFECTS COATING APPROACH GAS-STORAGE POROSITY ENHANCE FACILE UIO-66 Metal-organic frameworks Water stability Thermal treatment Hexatopic ligand Hydrogen storage