Carbon-13 nuclear magnetic resonance of simple molecules adsorbed on catalytic surfaces

Denney, Dorothy Z.; Мастихин, В. М.; Namba, Seitarô; Turkevich, John

doi:10.1021/j100504a019

Cited by 31 publications

(11 citation statements)

References 4 publications

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“…18,19 Chemical shifts of −10 to −12 ppm are characteristic for pure gaseous 13 CH 4 . 33,34,49 The deviation between the chemical shift in the pure phase and the gas mixture studied here is decent and can be attributed to interactions between the different gas molecules at the relatively high applied pressure and/or the low measurement temperature.…”

Section: ■ Results and Discussionmentioning

confidence: 87%

“…Pressure increase to 1.8 bar results in an increasing amount of adsorbed methane accompanied by a shift of the adsorbed 13 CH 4 signal to −6.9 ppm. A few ppm shift to more positive values relative to the gas-phase 13 C NMR signal are typical for adsorbed methane in porous materials such as zeolites and related compounds. − …”

Section: Results and Discussionmentioning

confidence: 99%

“…13 C solid-state NMR spectroscopy is a well-established technique to study adsorbed CO 2 in porous materials such as MOFs. − The adsorption of CH 4 on porous media was also studied previously by NMR spectroscopy. − Pulsed-field gradient NMR spectroscopy can be used to study diffusion processes of CO 2 and CH 4 in MOFs. , …”

Section: Introductionmentioning

confidence: 99%

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In Situ ¹³C NMR Spectroscopy Study of CO₂/CH₄ Mixture Adsorption by Metal–Organic Frameworks: Does Flexibility Influence Selectivity?

et al. 2019

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Metal–organic frameworks are promising candidates for selective separation processes such as CO2 removal from methane (natural gas sweetening). Framework flexibility, that is, the ability of a MOF lattice to change its structure as a function of parameters like pressure, temperature, and type of adsorbed molecules, is only observed for some special compounds. The main question of our present work is: does framework flexibility influence the adsorption selectivity? As a direct quantitative method to monitor the adsorption of both, carbon dioxide and methane, we make use of high-pressure in situ 13C NMR spectroscopy of 13CO2/13CH4 gas mixtures. This method allows to distinguish between the two gases as well as between adsorbed molecules and the interparticle gas phase. Gas mixture adsorption is studied under isothermal conditions. The selectivity factor for CO2 adsorption from CO2/CH4 mixtures is measured as a function of total gas pressure. The flexible material SNU-9 as well as the flexible and the nonflexible variant of DUT-8(Ni) are compared. Maximum selectivity factors for CO2 are observed for the flexible variant of DUT-8(Ni) in its open, large-pore state. In contrast, the rigid variant of DUT-8(Ni) and SNU-9 especially in its intermediate state exhibits lower adsorption selectivity factors. This observation indicates significant influence of the framework elasticity on the adsorption selectivity.

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Section: ■ Results and Discussionmentioning

confidence: 87%

Section: Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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In Situ ¹³C NMR Spectroscopy Study of CO₂/CH₄ Mixture Adsorption by Metal–Organic Frameworks: Does Flexibility Influence Selectivity?

et al. 2019

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“…It is noteworthy, however, that the calculation based on one-component isotherms may not correspond to real multicomponent adsorption. Recently, a few reports have investigated flexibility during multicomponent experiments; 25 , 26 , 57 however, this type of investigation is still rare and sought after. There are still open questions.…”

Section: Resultsmentioning

confidence: 99%

Combining In Situ Techniques (XRD, IR, and ¹³C NMR) and Gas Adsorption Measurements Reveals CO₂-Induced Structural Transitions and High CO₂/CH₄ Selectivity for a Flexible Metal–Organic Framework JUK-8

Roztocki

Rauche

Bon

et al. 2021

ACS Appl. Mater. Interfaces

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Flexible metal–organic frameworks (MOFs) are promising materials in gas-related technologies. Adjusting the material to processes requires understanding of the flexibility mechanism and its influence on the adsorption properties. Herein, we present the mechanistic understanding of CO 2 -induced pore-opening transitions of the water-stable MOF JUK-8 ([Zn(oba)(pip)] n , oba 2– = 4,4′-oxybis(benzenedicarboxylate), pip = 4-pyridyl-functionalized benzene-1,3-dicarbohydrazide) as well as its potential applicability in gas purification. Detailed insights into the global structural transformation and subtle local MOF–adsorbate interactions are obtained by three in situ techniques (XRD, IR, and 13 CO 2 -NMR). These results are further supported by single-crystal X-ray diffraction (SC-XRD) analysis of the solvated and guest-free phases. High selectivity toward carbon dioxide derived from the single-gas adsorption experiments of CO 2 (195 and 298 K), Ar (84 K), O 2 (90 K) , N 2 (77 K), and CH 4 (298 K) is confirmed by high-pressure coadsorption experiments of the CO 2 /CH 4 (75:25 v/v) mixture at different temperatures (288, 293, and 298 K) and in situ NMR studies of the coadsorption of 13 CO 2 / 13 CH 4 (50:50 v/v; 195 K).

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“…This line broadening can prevent the identification of individual 1 H resonances due to the limited chemical shift range associated with the 1 H nucleus. In contrast, the much larger chemical shift range of 13 C means that it is possible to distinguish the individual resonances even for the broadened lines of adsorbed molecules, 10 hence the surface interaction of each individual carbon atom in an adsorbed hydrocarbon can be examined.…”

Section: Introductionmentioning

confidence: 99%

Determining adsorbate configuration on alumina surfaces with ¹³C nuclear magnetic resonance relaxation time analysis

Vecino

Huang

Mitchell

et al. 2015

Phys. Chem. Chem. Phys.

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Relative strengths of surface interaction for individual carbon atoms in acyclic and cyclic hydrocarbons adsorbed on alumina surfaces are determined using chemically resolved (13)C nuclear magnetic resonance (NMR) T1 relaxation times. The ratio of relaxation times for the adsorbed atoms T1,ads to the bulk liquid relaxation time T1,bulk provides an indication of the mobility of the atom. Hence a low T1,ads/T1,bulk ratio indicates a stronger surface interaction. The carbon atoms associated with unsaturated bonds in the molecules are seen to exhibit a larger reduction in T1 on adsorption relative to the aliphatic carbons, consistent with adsorption occurring through the carbon-carbon multiple bonds. The relaxation data are interpreted in terms of proximity of individual carbon atoms to the alumina surface and adsorption conformations are inferred. Furthermore, variations of interaction strength and molecular configuration have been explored as a function of adsorbate coverage, temperature, surface pre-treatment, and in the presence of co-adsorbates. This relaxation time analysis is appropriate for studying the behaviour of hydrocarbons adsorbed on a wide range of catalyst support and supported-metal catalyst surfaces, and offers the potential to explore such systems under realistic operating conditions when multiple chemical components are present at the surface.

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Carbon-13 nuclear magnetic resonance of simple molecules adsorbed on catalytic surfaces

Cited by 31 publications

References 4 publications

In Situ ¹³C NMR Spectroscopy Study of CO₂/CH₄ Mixture Adsorption by Metal–Organic Frameworks: Does Flexibility Influence Selectivity?

In Situ ¹³C NMR Spectroscopy Study of CO₂/CH₄ Mixture Adsorption by Metal–Organic Frameworks: Does Flexibility Influence Selectivity?

Combining In Situ Techniques (XRD, IR, and ¹³C NMR) and Gas Adsorption Measurements Reveals CO₂-Induced Structural Transitions and High CO₂/CH₄ Selectivity for a Flexible Metal–Organic Framework JUK-8

Determining adsorbate configuration on alumina surfaces with ¹³C nuclear magnetic resonance relaxation time analysis

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Carbon-13 nuclear magnetic resonance of simple molecules adsorbed on catalytic surfaces

Cited by 31 publications

References 4 publications

In Situ 13C NMR Spectroscopy Study of CO2/CH4 Mixture Adsorption by Metal–Organic Frameworks: Does Flexibility Influence Selectivity?

In Situ 13C NMR Spectroscopy Study of CO2/CH4 Mixture Adsorption by Metal–Organic Frameworks: Does Flexibility Influence Selectivity?

Combining In Situ Techniques (XRD, IR, and 13C NMR) and Gas Adsorption Measurements Reveals CO2-Induced Structural Transitions and High CO2/CH4 Selectivity for a Flexible Metal–Organic Framework JUK-8

Determining adsorbate configuration on alumina surfaces with 13C nuclear magnetic resonance relaxation time analysis

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Product

Resources

About

In Situ ¹³C NMR Spectroscopy Study of CO₂/CH₄ Mixture Adsorption by Metal–Organic Frameworks: Does Flexibility Influence Selectivity?

In Situ ¹³C NMR Spectroscopy Study of CO₂/CH₄ Mixture Adsorption by Metal–Organic Frameworks: Does Flexibility Influence Selectivity?

Combining In Situ Techniques (XRD, IR, and ¹³C NMR) and Gas Adsorption Measurements Reveals CO₂-Induced Structural Transitions and High CO₂/CH₄ Selectivity for a Flexible Metal–Organic Framework JUK-8

Determining adsorbate configuration on alumina surfaces with ¹³C nuclear magnetic resonance relaxation time analysis