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.

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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 B- and N-doped microporous carbon has been synthesized via a substitution reaction. The obtained carbon exhibited much higher surface area than the previously reported B- and N-doped carbon. The hydrogen storage measurements indicated that the B- and N-doped microporous carbon had a 53% higher storage capacity than the carbon materials with similar surface areas. Furthermore, hydrogen storage via spillover was studied on Ru-supported B- and N-doped microporous carbon and a storage capacity of 1.2 wt % at 298 K and 10 MPa was obtained, showing an enhancement factor of 2.2. Ab initio molecular orbital calculations were also performed for the binding energies between the spiltover hydrogen atom and various sites on the doped carbon. The theoretical calculations can explain the experimental results well, which also shed light on the most favorable and possible sites with which the spiltover hydrogen atoms bind. V V C 2009 American Institute of Chemical Engineers AIChE J, 55: 1823–1833,

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Hydrogen storage properties of B‐ and N‐doped microporous carbon

Organonitrogen compounds are present in commercial fuels after the hydrodenitrogenation process in quantities up to a few hundred ppmw N. Polyaromatic hydrocarbons (PAH) are present in significant quantities (1.4−11 wt %) in transportation fuels depending on both the region and season. In this work, the effect of organonitrogen (quinoline, carbazole) and PAH (naphthalene, fluorene, phenanthrene) compounds on desulfurization by π-complexation with Cu(I)Y zeolite was studied and found to be moderate. The high selectivity for sulfur was not affected because a very low-sulfur fuel ( quinoline ...

Effects of Nitrogen Compounds and Polyaromatic Hydrocarbons on Desulfurization of Liquid Fuels by Adsorption via π-Complexation with Cu(I)Y Zeolite

Electronic structure methods applied to gas–carbon reactions

Gold decoration of the basal lattice plane of graphite etched by atomic oxygen has been made possible by first desorbing the surface oxide layer on the basal plane. The formation of monolayer pits, as revealed by gold decoration, shows that anisotropy does exist, i.e., carbon atoms are preferentially attacked by atomic oxygen in the direction of a axes, rather than the direction of c axis. The monolayer pits are initiated from lattice vacancies which are continually formed by atomic oxygen. The monolayer pits created by atomic oxygen are, unlike the pits by O2 which are circular, hexagonal in shape, the sides of which are composed of 〈101l〉 lattice planes.

Ralph T. Yang

Papers

Hydrogen storage properties of B‐ and N‐doped microporous carbon

Effects of Nitrogen Compounds and Polyaromatic Hydrocarbons on Desulfurization of Liquid Fuels by Adsorption via π-Complexation with Cu(I)Y Zeolite

Electronic structure methods applied to gas–carbon reactions

The mode of attack of oxygen atoms on the basal plane of graphite

Scanning tunneling microscope study of electropolymerized polypyrrole with polymeric anion