Crystalline metal-organic frameworks (MOFs) are formed by reticular synthesis, which creates strong bonds between inorganic and organic units. Careful selection of MOF constituents can yield crystals of ultrahigh porosity and high thermal and chemical stability. These characteristics allow the interior of MOFs to be chemically altered for use in gas separation, gas storage, and catalysis, among other applications. The precision commonly exercised in their chemical modification and the ability to expand their metrics without changing the underlying topology have not been achieved with other solids. MOFs whose chemical composition and shape of building units can be multiply varied within a particular structure already exist and may lead to materials that offer a synergistic combination of properties.

The Chemistry and Applications of Metal-Organic Frameworks

New materials hold the key to fundamental advances in energy conversion and storage, both of which are vital in order to meet the challenge of global warming and the finite nature of fossil fuels. Nanomaterials in particular offer unique properties or combinations of properties as electrodes and electrolytes in a range of energy devices. This review describes some recent developments in the discovery of nanoelectrolytes and nanoelectrodes for lithium batteries, fuel cells and supercapacitors. The advantages and disadvantages of the nanoscale in materials design for such devices are highlighted.

https://img62.chem17.com/1/20140715/635410323829886334962.pdf

Nanostructured materials for advanced energy conversion and storage devices

Adsorptive separation is very important in industry. Generally, the process uses porous solid materials such as zeolites, activated carbons, or silica gels as adsorbents. With an ever increasing need for a more efficient, energy-saving, and environmentally benign procedure for gas separation, adsorbents with tailored structures and tunable surface properties must be found. Metal–organic frameworks (MOFs), constructed by metal-containing nodes connected by organic bridges, are such a new type of porous materials. They are promising candidates as adsorbents for gas separations due to their large surface areas, adjustable pore sizes and controllable properties, as well as acceptable thermal stability. This critical review starts with a brief introduction to gas separation and purification based on selective adsorption, followed by a review of gas selective adsorption in rigid and flexible MOFs. Based on possible mechanisms, selective adsorptions observed in MOFs are classified, and primary relationships between adsorption properties and framework features are analyzed. As a specific example of tailor-made MOFs, mesh-adjustable molecular sieves are emphasized and the underlying working mechanism elucidated. In addition to the experimental aspect, theoretical investigations from adsorption equilibrium to diffusion dynamics via molecular simulations are also briefly reviewed. Furthermore, gas separations in MOFs, including the molecular sieving effect, kinetic separation, the quantum sieving effect for H2/D2 separation, and MOF-based membranes are also summarized (227 references).

Selective gas adsorption and separation in metal–organic frameworks

Metal–Organic Frameworks for Separations

Kenji Sumida, David L. Rogow, Jarad A. Mason, Thomas M. McDonald, Eric D. Bloch, Zoey R. Herm, Tae-Hyun Bae, Jeffrey R. Long

Carbon Dioxide Capture in Metal–Organic Frameworks

A series of Pt-doped IRMOF-8 samples with different Pt catalyst sizes have been prepared via organometallic chemical-vapor deposition (CVD). The Pt catalyst size effects on the spillover storage on IRMOF-8 (or any MOF) were studied for the first time. Our studies showed that the Pt catalyst size is a crucial factor determining whether a significant enhancement in storage can be achieved in the hydrogen spillover system at ambient temperature. Compared to undoped IRMOF-8, the spillover storage capacities on Pt-doped IRMOF-8 samples were enhanced by factors ranging from 1.1 to 1.9 because of different Pt catalyst sizes. The doped Pt size was controlled by varying the CVD conditions to yield mean sizes of 2.2, 3.9, and 9.1 nm, and the results showed that smaller sizes were needed for spillover. Temperature-programmed desorption of dosed H2/D2 further shed light on the mechanism of spillover and reverse spillover, confirming undercoordinated sites on the particle-enhanced spillover.

Effects of Pt Particle Size on Hydrogen Storage on Pt-Doped Metal―Organic Framework IRMOF-8

A series of graphite nanofibers (GNFs) that were subjected to various pretreatments were used to determine how modifications in the carbon structure formed during either synthesis or pretreatment steps results in active or inactive materials for hydrogen storage. The nanofibers possessing a herringbone structure and a high degree of defects were found to exhibit the best performance for hydrogen storage. These materials were exposed to several pretreatment procedures, including oxidative, reductive, and inert environments. Significant hydrogen storage levels were found for several in situ pretreatments. Examination of the nanofibers by high-resolution transmission electron microscopy (TEM) after pretreatment and subsequent hydrogen storage revealed the existence of edge attack and an enhancement in the generation of structural defects. These findings suggest that pretreatment in certain environments results in the creation of catalytic sites that are favorable toward hydrogen storage. The best pretreatment resulted in a 3.8% hydrogen release after exposure at 69 bar and room temperature.

Hydrogen Storage in Graphite Nanofibers: Effect of Synthesis Catalyst and Pretreatment Conditions

Selective catalytic reduction of nitric oxide with hydrogen over Pd based catalysts

Presentation d'une equation de Dubinin Radushkevich modifiee pour l'adsorption de gaz sur des materiaux microporeux

On the Dubinin-Radushkevich equation for adsorption in microporous solids in the Henry's law region

Hydrogen storage in MWNT was enhanced ®ia the catalytic acti®ity of NiMgO. The magnitude of the hydrogen to metal ratio for the MWNTrNiMgO system, combined with temperature programmed adsorption and desorption studies, showed hydrogen spillo®er from the catalyst to the carbon surface. Metal doping combined with temperature acti®ation studies showed that both nickel and magnesium are acti®e in the catalytic process. The yield, quality, and carbon-metal contact were shown to affect hydrogen uptake. Higher pretreatment temperatures enhanced uptake, for both low- and high-pressure measurements, due to increased carbon-metal contact and acti®ation of () the catalyst. At 69 bar or 1,000 psia , the hydrogen adsorption and desorption of the MWNTrNiMgO system were 3.7% and 3.6%, respecti®ely.

https://deepblue.lib.umich.edu/bitstream/handle/2027.42/34249/690490619_ftp.pdf;sequence=1

Ralph T. Yang

Papers

Effects of Pt Particle Size on Hydrogen Storage on Pt-Doped Metal―Organic Framework IRMOF-8

Hydrogen Storage in Graphite Nanofibers: Effect of Synthesis Catalyst and Pretreatment Conditions

Selective catalytic reduction of nitric oxide with hydrogen over Pd based catalysts

On the Dubinin-Radushkevich equation for adsorption in microporous solids in the Henry's law region

Hydrogen storage in carbon nanotubes: Residual metal content and pretreatment temperature