Regulating defected zirconium metal–organic frameworks in ionic liquid for sewage treatment

Engineering Porosity and Functionality in a Robust Twofold Interpenetrated Bismuth-Based MOF: Toward a Porous, Stable, and Photoactive Material

“…The most defective MOF (Bi-TATAB-150) showed ∼450- and 29-times higher surface area and pore volume, respectively, compared to the theoretical values of the defect-free Bi-TATAB model and ∼3- and 2-times higher than the least defective MOF (Bi-TATAB-60). Similar findings were previously reported, where higher surface areas and/or larger accessible pore volumes were correlated to the defects density in natively porous MOFs. ,,,,,,,,,,− In contrast to that, Bi-TATAB is a benchmark material where defects not only progressively enhanced the porosity but also converted a natively nonporous material to a porous structure for potential adsorption applications while retaining high crystallinity and framework stability. This finding is critical as it emphasizes the importance of experimental exploitation of many MOFs that are otherwise discarded during preliminary theoretical analysis due to the nonporous nature of their model. , …”

“…As shown in Figure S12, the defect-rich Bi-TATAB- X MOFs ( i.e ., at X = 110, 130, and 150) revealed hybrid type-I­(b) and type IV­(a) isotherms, validating the micromesoporous nature of the aforementioned MOFs. , In case of Bi-TATAB- X MOFs with fewer defects ( i.e ., X = 60 or 90), at higher relative pressures, isotherms deviated more toward type II behavior, giving rise to mesopores or narrow macropores. ,, Likewise, this kind of deviation was previously reported for other MOFs with missing linkers and/or MOFs prepared with prolonged crystallization durations. , Besides, all samples, except Bi-TATAB-60, showed desorption hysteresis behavior of H2-type. , The hysteresis occurrence and associated wide mesoporosity (Figures S12 and S13) can be reasonably ascribed to the large-scale defects, ,,,, which originated as a combination of point defect-clusters or excessive linker vacancies. ,, Unlike most reported cases of LSMD in MOFs, which cause a decline in specific surface area and/or structure collapse, ,,,, the defect-induced augmented porosity (micro- and wide mesopores) in Bi-TATAB- X MOFs does not alter the framework stability. The robustness of the interpenetrated framework may be the origin of this apparent anomaly.…”

“…35,57 In case of Bi-TATAB-X MOFs with fewer defects (i.e., X = 60 or 90), at higher relative pressures, isotherms deviated more toward type II behavior, giving rise to mesopores or narrow macropores. 13,25,57 Likewise, this kind of deviation was previously reported for other MOFs with missing linkers and/or MOFs prepared with prolonged crystallization durations. 13,25 Besides, all samples, except Bi-TATAB-60, showed desorption hysteresis behavior of H2-type.…”

“…13,25,57 Likewise, this kind of deviation was previously reported for other MOFs with missing linkers and/or MOFs prepared with prolonged crystallization durations. 13,25 Besides, all samples, except Bi-TATAB-60, showed desorption hysteresis behavior of H2-type. 22,57 The hysteresis occurrence and associated wide mesoporosity (Figures S12 and S13) can be reasonably ascribed to the large-scale defects, 6,16,22,58,59 which originated as a combination of point defect-clusters or excessive linker vacancies.…”

“…Metal–organic frameworks (MOFs) are highly crystalline porous materials built by the ordered assembly of metal nodes and/or clusters and organic ligands. Owing to their porous nature, tunability, structure diversity, and functionalities, MOFs have gained great attention for a wide array of applications, e.g ., gas adsorption, − separation, storage, , catalysis, − biomedicine, selective sensing, , environmental remediation, − etc . Parallel to the predominant research focus on optimizing the synthetic parameters to get flawless “defect-free” ordered MOF crystals, over the past decade, researchers have ventured into a new direction to target “controlled defect generation” within the framework, aka “defect engineering.” The defect sites in MOFs endow them with distinctive structural and physicochemical features that are absent in the defect-free analogue.…”