The emergence of metal-organic frameworks (MOFs) as func-tional ultrahigh surface area materials is one of the most excit-ing recent developments in solid-state chemistry. Now constituting thousands of distinct examples, MOFs are an intriguing class of hybrid materials that exist as infinite crystalline lattices with inor-ganic vertices and molecular-scale organic connectors. Useful prop-erties such as large internal surface areas, ultralow densities, and the availability of uniformly structured cavities and portals of molecular dimensions characterize functional MOFs. Researchers have effectively exploited these unusual properties in applica-tions such as hydrogen and methane storage, chemical separa-tions, and selective chemical catalysis. In principle, one of the most attractive features of MOFs is the simplicity of their synthesis. Typically they are obtained via one-pot solvothermal preparations. However, with the simplicity come challenges. In particular, MOF materials, especially more complex ones, can be difficult to obtain in pure form and with the optimal degree of catenation, the interpenetration or inter-

Metal–organic frameworks (MOFs) are porous materials constructed from modular molecular building blocks, typically metal clusters and organic linkers. These can, in principle, be assembled to form an almost unlimited number of MOFs, yet materials reported to date represent only a tiny fraction of the possible combinations. Here, we demonstrate a computational approach to generate all conceivable MOFs from a given chemical library of building blocks (based on the structures of known MOFs) and rapidly screen them to find the best candidates for a specific application. From a library of 102 building blocks we generated 137,953 hypothetical MOFs and for each one calculated the pore-size distribution, surface area and methane-storage capacity. We identified over 300 MOFs with a predicted methane-storage capacity better than that of any known material, and this approach also revealed structure–property relationships. Methyl-functionalized MOFs were frequently top performers, so we selected one such promising MOF and experimentally confirmed its predicted capacity. H ighly porous materials have widespread applications in the manipulation of small molecules for gas storage1–6, separ-ating mixtures7–12, catalysis13,14, analysis and detection15–17. Among the many types of porous materials18,19, metal–organic

Abstract not found

ABSTRACT: Metal−organic frameworks (MOFs), a class of porous materials, are of particular interest in gas storage and separation applications due largely to their high internal surface areas and tunable structures. MOF-5 is perhaps the archetypal MOF; in particular, many isoreticular analogues of MOF-5 have been synthesized, comprising alternative dicarboxylic acid ligands. In this contribution we introduce a new set of hypothesized MOF-5 analogues, constructed from commercially available organic molecules. We describe our automated procedure for hypothetical MOF design, comprising selection of appropriate ligands, construction of 3D structure models, and structure relaxation methods. 116 MOF-5 analogues were designed and characterized in terms of geometric properties and simulated methane uptake at conditions relevant to vehicular storage applications. A strength of the presented approach is that all of the hypothesized MOFs are designed to be synthesizable utilizing ligands purchasable online. Metal−organic frameworks1 (MOFs) are a class of porous materials comprised of metal or metal oxide vertices

Fault diagnosis of rolling bearing based on wavelet transform and envelope spectrum correlation

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bS Supporting Information Hydrogen has been identified as a most promising fuel formeeting our future energy needs; however, there are difficulties in storage and retrieving the hydrogen once stored.2 Metal-based and chemical storage systems are capable of stor-ing sufficient H2 to meet the US DOE goals for transportation; 3 however, they involve HH bond breaking and formation processes that lead to rates that are far too slow for modern applications. Systems based on physisorption of the H2 mol-ecules have sufficient rates, but the adsorption energies are low, so that the best-performing such material, MOF-177, stores only 1.3 % wt H2 at 270 K. 4 Hexagonal ice (ice Ih) is the natural form of ice in snow and the upper atmosphere, and is the thermodynamically favored ice

ligands: from coordination polymers to anticancer drug precursors.

The research on hydrogen generation and application has attracted widespread attention around the world. This paper is to demonstrate that sodium aluminum hydride can be synthesized under simple and mild reaction condition. Being activated through organics, aluminum powder reacts with hydrogen and sodium hydride to produce sodium aluminum hydride under atmospheric pressure. The properties and composition of the sample were characterized by FTIR, XRD, SEM, and so forth. The results showed that the product through this synthesis method is sodium aluminum hydride, and it has higher purity, perfect crystal character, better stability, and good hydrogen storage property. The reaction mechanism is also discussed in detail.

Hydrogen has been identified as a most promising fuel formeeting our future energy needs; however, there are difficulties in storage and retrieving the hydrogen once stored.2 Metal-based and chemical storage systems are capable of stor-ing sufficient H2 to meet the US DOE goals for transportation; 3 however, they involve HH bond breaking and formation processes that lead to rates that are far too slow for modern applications. Systems based on physisorption of the H2 mol-ecules have sufficient rates, but the adsorption energies are low, so that the best-performing such material, MOF-177, stores only 1.3 % wt H2 at 270 K. 4 Hexagonal ice (ice Ih) is the natural form of ice in snow and the upper atmosphere, and is the thermodynamically favored ice phase from 180 to 273K and 0 to 1GPa (10 000 bar ≈ 10 000 atm).