Dataset Information

Porous Metal-Organic Polyhedral Frameworks with Optimal Molecular Dynamics and Pore Geometry for Methane Storage.

ABSTRACT: Natural gas (methane, CH₄) is widely considered as a promising energy carrier for mobile applications. Maximizing the storage capacity is the primary goal for the design of future storage media. Here we report the CH₄ storage properties in a family of isostructural (3,24)-connected porous materials, MFM-112a, MFM-115a, and MFM-132a, with different linker backbone functionalization. Both MFM-112a and MFM-115a show excellent CH₄ uptakes of 236 and 256 cm³ (STP) cm^-3 (v/v) at 80 bar and room temperature, respectively. Significantly, MFM-115a displays an exceptionally high deliverable CH₄ capacity of 208 v/v between 5 and 80 bar at room temperature, making it among the best performing metal-organic frameworks for CH₄ storage. We also synthesized the partially deuterated versions of the above materials and applied solid-state ²H NMR spectroscopy to show that these three frameworks contain molecular rotors that exhibit motion in fast, medium, and slow regimes, respectively. In situ neutron powder diffraction studies on the binding sites for CD₄ within MFM-132a and MFM-115a reveal that the primary binding site is located within the small pocket enclosed by the [(Cu₂)₃(isophthalate)₃] window and three anthracene/phenyl panels. The open Cu(II) sites are the secondary/tertiary adsorption sites in these structures. Thus, we obtained direct experimental evidence showing that a tight cavity can generate a stronger binding affinity to gas molecules than open metal sites. Solid-state ²H NMR spectroscopy and neutron diffraction studies reveal that it is the combination of optimal molecular dynamics, pore geometry and size, and favorable binding sites that leads to the exceptional and different methane uptakes in these materials.

SUBMITTER: Yan Y

PROVIDER: S-EPMC5620961 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Several synthetic methods have recently emerged to develop high-surface-area solid-state organic framework-based materials into free-flowing liquids with permanent porosity. The fluidity of these porous liquid (PL) materials provides them with advantages in certain storage and transport processes. However, most framework-based materials necessitate the use of cryogenic temperatures to store weakly bound gases such as H2, temperatures where PLs lose their fluidity. Covalent organic framework (COF)-based PLs that could reversibly form stable complexes with H2 near ambient temperatures would represent a promising development for gas storage and transport applications. We report here the development, characterization, and evaluation of a material with these remarkable characteristics based on Cu(I)-loaded COF colloids. Our synthetic strategy required tailoring conditions for growing robust coatings of poly(dimethylsiloxane)-methacrylate (PDMS-MA) around COF colloids using atom transfer radical polymerization (ATRP). We demonstrate exquisite control over the coating thickness on the colloidal COF, quantified by transmission electron microscopy and dynamic light scattering. The coated COF material was then suspended in a liquid polymer matrix to make a PL. CO2 isotherms confirmed that the coating preserved the general porosity of the COF in the free-flowing liquid, while CO sorption measurements using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) confirmed the preservation of Cu(I) coordination sites. We then evaluated the gas sorption phenomenon in the Cu(I)-COF-based PLs using DRIFTS and temperature-programmed desorption measurements. In addition to confirming that H2 transport is possible at or near mild refrigeration temperatures with these materials, our observations indicate that H2 diffusion is significantly influenced by the glass-transition temperature of both the coating and the liquid matrix. The latter result underscores an additional potential advantage of PLs in tailoring gas diffusion and storage temperatures through the coating composition.

Dataset Information

Porous Metal-Organic Polyhedral Frameworks with Optimal Molecular Dynamics and Pore Geometry for Methane Storage.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets