Adsorption properties of acetylene, ethylene and ethane in UiO-66 with linker defects and NO<sub>2</sub> functionalization

Pandey, Haardik; Barrett, Taylor; Gross, Michael D.; Thonhauser, Timo

doi:10.1039/d0ma00722f

Cited by 3 publications

(7 citation statements)

References 73 publications

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“…At near-zero loadings, ethylene molecules adsorb with energies of up to 35 kJ/mol on the metal nodes, which is comparable for all three materials considering the uncertainty intervals for low loadings. 31 The heats of adsorption decrease to ∼20 kJ/mol at an ethylene loading of about 0.7−0.8 mmol/g and then increase again due to intermolecular interactions between adsorbed molecules via π−π interactions. The heats of adsorption for ethylene are higher than that for carbon dioxide for loadings smaller than ∼0.2 mmol/g, but the reverse is true for higher loadings.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…For this study, UiO-66 was chosen as the baseline framework due to its stability and tunability. ,, The framework was modified through the controlled, stepwise incorporation of amine functionalization to enable specific interactions with the selected probe molecules. Carbon dioxide and ethylene can interact with the amine groups based on their quadrupole moments and the π-double bond in ethylene. − Moreover, similar total loadings of these probe molecules at a given pressure in UiO-66 and its derivatives suggest competitive adsorption due to similar adsorption affinities, which has been reported to result in deviations from IAST predictions, highlighting the importance of studying these systems. , Additionally, these probe molecules are present in the off-gas mixture in acetaldehyde production, emphasizing their relevance in real applications …”

Section: Introductionmentioning

confidence: 99%

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Does Mixed Linker-Induced Surface Heterogeneity Impact the Accuracy of IAST Predictions in UiO-66-NH₂?

Bingel,

Yu,

Sholl

et al. 2023

J. Phys. Chem. C

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To move toward more energy-efficient adsorption-based processes, there is a need for accurate multicomponent data under realistic conditions. While the Ideal Adsorbed Solution Theory (IAST) has been established as the preferred prediction method due to its simplicity, limitations and inaccuracies for less ideal adsorption systems have been reported. Here, we use amine-functionalized derivatives of the UiO-66 structure to change the extent of homogeneity of the internal surface toward the adsorption of the two probe molecules carbon dioxide and ethylene. Although it might seem plausible that more functional groups lead to more heterogeneity and, thus, less accurate predictions by IAST, we find a mixedlinker system with increased heterogeneity in terms of added adsorption sites where IAST predictions and experimental loadings agree exceptionally well. We show that incorporating uncertainty analysis into predictions with IAST is important for assessing the accuracy of these predictions. Energetic investigations combined with Grand Canonical Monte Carlo simulations reveal almost homogeneous carbon dioxide but heterogeneous ethylene adsorption in the mixed-linker material, resulting in local, almost pure phases of the individual components.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Does Mixed Linker-Induced Surface Heterogeneity Impact the Accuracy of IAST Predictions in UiO-66-NH₂?

Bingel,

Yu,

Sholl

et al. 2023

J. Phys. Chem. C

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“…14,15 Using acetic acid as a modulator, defected UiO-66s were obtained with functional groups (hydroxyl or nitro) remained in the framework. 15,16 In post-synthesis methods for defect construction, adding an additional acid/base or heating the formed MOFs is usually performed to disconnect the ligand with metal centers. For instance, Gu et al 17 treated synthesized MOF-808 with hydrochloric acid, which destroyed part of connections between ligands and the metal cluster and defect sites and then formed.…”

Section: Introductionmentioning

confidence: 99%

“…Similarly, the pore size of MOFs was controlled in the range of 20 nm–1 μm by using different types and concentrations of modulators . Moreover, using modulators with lower p K a and higher concentration will lead to more defects in the framework, which also proved feasible in other types of MOFs. , Using acetic acid as a modulator, defected UiO-66s were obtained with functional groups (hydroxyl or nitro) remained in the framework. , …”

Section: Introductionmentioning

confidence: 99%

Magnetic S-Functionalized Nanoporous Zr-Metal Organic Frameworks with Defect-Induced Performance in Hg(II) Removal

Xu,

He,

Chen

et al. 2023

ACS Appl. Nano Mater.

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Defect engineering has been widely used in improving metal−organic framework (MOF) performance. Herein, magnetic nanoporous S-functionalized MOF-808 (MMOF-808-S-D) was synthesized through a large mixed-ligand defect constructing strategy with modulated synthesis. Defect was constructed due to the existence of a larger heterogeneous ligand (tetracarboxyporphyrin, TCPP), which leads to loss of connection between the metal cluster and the original ligand of MOF-808 based on the steric hindrance effect. The proportion of TCPP was optimized as 10% with little influence on crystallization of MOF-808, but more unsaturated Zr−O binding sites were exposed to connect to the S-containing modulator, which makes more S modified on the framework. MMOF-808-S-D exhibits high S content (10.6% wt.) and considerable adsorption performance for Hg(II) in terms of high adsorption capacity (350 mg g −1 ), fast adsorption kinetics (0.95 g mg −1 min −1 ), and good regeneration ability among reported magnetic framework materials. MMOF-808-S-D can be used for removing Hg(II) in different aqueous solution matrixes effectively, while the magnetism makes phase separation simple, exhibiting great potential in environmental remediations. Besides, the defect construction-involved functionalization strategy can be universally extended to other types of MOFs and improve the performance of defected MOFs in practical application.

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“…Although information of structural evolutions during gate-opening phenomenasuch as pressure-induced global structural phase transitions or local changes like ligand twisting, rotations, bending or tilting movements, ,− and snapshot analyses from single-crystal X-ray diffraction (XRD)are important, the high degree of structural displacement in flexible MOFs (usually causing cracking of single crystals , ) makes such measurements challenging and only a few are reported. , As such, indirect approaches like isotherm measurements are often used to characterize sorbate–sorbent interactions − or H-bonding interactions between the guest and host (which can lead to interesting dynamic behavior in separation, functionality, and adsorption or desorption). The enthalpy of adsorption is mostly measured using a variety of indirect approaches or calorimetry techniques in combination with isotherm measurements − but direct calorimetry measurements of adsorption in MOFs are rare. − However, despite the quantification of various adsorption features, most of them are not directly linked to gate-opening phenomena in flexible MOFs.…”

Section: Introductionmentioning

confidence: 99%

Identifying the Gate-Opening Mechanism in the Flexible Metal–Organic Framework UTSA-300

et al. 2022

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Atomic-level understanding of the gate-opening phenomenon in flexible porous materials is an important step toward learning how to control, design, and engineer them for applications such as the separation of gases from complex mixtures. Here, we report such mechanistic insight through an in-depth study of the pressure-induced gate-opening phenomenon in our earlier reported metal–organic framework (MOF) Zn(dps)2(SiF6) (dps = 4,4′-dipyridylsulfide), also called UTSA-300, using isotherm and calorimetry measurements, in situ infrared spectroscopy, and ab initio simulations. UTSA-300 is shown to selectively adsorb acetylene (C2H2) over ethylene (C2H4) and ethane (C2H6) and undergoes an abrupt gate-opening phenomenon, making this framework a highly selective gas separator of this complex mixture. The selective adsorption is confirmed by pressure-dependent in situ infrared spectroscopy, which, for the first time, shows the presence of multiple C2H2 species with varying strengths of bonding. A rare energetic feature at the gate-opening condition of the flexible MOF is observed in our differential heat energies, directly measured by calorimetry, showcasing the importance of this tool in adsorption property exploration of flexible frameworks and offering an energetic benchmark for further energy-based fundamental studies. Based on the agreement of this feature with ab initio-based adsorption energies of C2H2 in the closed-pore structure UTSA-300a (“a” refers to the activated form), this feature is assigned to the weakening of the H-bond C–H···F formed between C2H2 and fluorine of the MOF. Our analysis identifies the weakening of this H-bond, the expansion of the closed-pore MOF upon successive C2H2 coadsorption until its volume is close to that of the open-pore MOF, and the spontaneous gate opening to energetically favor C2H2 adsorption in the open-pore structure as crucial steps in the gate-opening mechanism in this system.

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Adsorption properties of acetylene, ethylene and ethane in UiO-66 with linker defects and NO₂ functionalization

Abstract: Using calorimetry and ab initio simulations, we uncover atomic-level details of the loading/separation process of C2 hydrocarbons in UiO-66.

Cited by 3 publications

References 73 publications

Does Mixed Linker-Induced Surface Heterogeneity Impact the Accuracy of IAST Predictions in UiO-66-NH₂?

Does Mixed Linker-Induced Surface Heterogeneity Impact the Accuracy of IAST Predictions in UiO-66-NH₂?

Magnetic S-Functionalized Nanoporous Zr-Metal Organic Frameworks with Defect-Induced Performance in Hg(II) Removal

Identifying the Gate-Opening Mechanism in the Flexible Metal–Organic Framework UTSA-300

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Adsorption properties of acetylene, ethylene and ethane in UiO-66 with linker defects and NO2 functionalization

Abstract: Using calorimetry and ab initio simulations, we uncover atomic-level details of the loading/separation process of C2 hydrocarbons in UiO-66.

Cited by 3 publications

References 73 publications

Does Mixed Linker-Induced Surface Heterogeneity Impact the Accuracy of IAST Predictions in UiO-66-NH2?

Does Mixed Linker-Induced Surface Heterogeneity Impact the Accuracy of IAST Predictions in UiO-66-NH2?

Magnetic S-Functionalized Nanoporous Zr-Metal Organic Frameworks with Defect-Induced Performance in Hg(II) Removal

Identifying the Gate-Opening Mechanism in the Flexible Metal–Organic Framework UTSA-300

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Adsorption properties of acetylene, ethylene and ethane in UiO-66 with linker defects and NO₂ functionalization

Does Mixed Linker-Induced Surface Heterogeneity Impact the Accuracy of IAST Predictions in UiO-66-NH₂?

Does Mixed Linker-Induced Surface Heterogeneity Impact the Accuracy of IAST Predictions in UiO-66-NH₂?