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Hydrogen Capacity (hydrogen + capacity)

Distribution by Scientific Domains
Polymers and Materials Science50%

Selected Abstracts

Hydrogen Storage in Metal,Organic Frameworks

ADVANCED MATERIALS, Issue 20 2010
Yun Hang Hu
Abstract Metal,organic frameworks (MOFs) are highly attractive materials because of their ultra-high surface areas, simple preparation approaches, designable structures, and potential applications. In the past several years, MOFs have attracted worldwide attention in the area of hydrogen energy, particularly for hydrogen storage. In this review, the recent progress of hydrogen storage in MOFs is presented. The relationships between hydrogen capacities and structures of MOFs are evaluated, with emphasis on the roles of surface area and pore size. The interaction mechanism between H2 and MOFs is discussed. The challenges to obtain a high hydrogen capacity at ambient temperature are explored. [source]

Novel organometallic fullerene complexes for vehicular hydrogen storage

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 11 2007
A. C. Dillon
Abstract Theoretical studies have predicted that scandium can bind to the twelve five-membered rings in C60. It is then possible to stabilize four dihydrogen ligands (H2) on each Sc atom with a binding energy of ,30 kJ/mol, ideal for vehicular hydrogen storage. The resulting C60[ScH2(H2)4]12 complex is predicted to be a minimum energy structure with ,7.0 wt% reversible hydrogen capacity. However, wet chemical synthesis of the calculated ,5 -coordinated fullerene complex is unprecedented. The chemistry of C60 is generally olefinic (i.e., ,2 -coordination, in which the metal is coordinated to two carbon atoms contributing two electrons to the bonding). Furthermore, stabilization of multiple dihydrogen ligands on a single transition metal has not been demonstrated. Recently we have probed new synthesis techniques in order to coordinate C60 with either Fe, Sc, Cr, Co or Li. The new compounds were characterized with solid-state nuclear magnetic resonance, and structures have been proposed. All of the structures were found to have unique binding sites for hydrogen employing the technique of temperature programmed desorption. Furthermore, some of the structures were shown to have significant hydrogen capacities with volumetric measurements. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Lithium-Catalyzed Dehydrogenation of Ammonia Borane within Mesoporous Carbon Framework for Chemical Hydrogen Storage

ADVANCED FUNCTIONAL MATERIALS, Issue 2 2009
Li Li
Abstract Ammonia borane (AB) has attracted tremendous interest for on-board hydrogen storage due to its low molecular weight and high gravimetric hydrogen capacity below a moderate temperature. However, the slow kinetics, irreversibility, and formation of volatile materials (trace borazine and ammonia) limit its practical application. In this paper, a new catalytic strategy involved lithium (Li) catalysis and nanostructure confinement in mesoporous carbon (CMK-3) for the thermal decomposition of AB is developed. AB loaded on the 5% Li/CMK-3 framework releases ,7,wt % of hydrogen at a very low temperature (around 60,°C) and entirely suppresses borazine and ammonia emissions that are harmful for proton exchange membrane fuel cells. The possible mechanism for enhanced hydrogen release via catalyzed thermal decomposition of AB is discussed. [source]

Hydrogen Storage in Metal,Organic Frameworks

ADVANCED MATERIALS, Issue 20 2010
Yun Hang Hu
Abstract Metal,organic frameworks (MOFs) are highly attractive materials because of their ultra-high surface areas, simple preparation approaches, designable structures, and potential applications. In the past several years, MOFs have attracted worldwide attention in the area of hydrogen energy, particularly for hydrogen storage. In this review, the recent progress of hydrogen storage in MOFs is presented. The relationships between hydrogen capacities and structures of MOFs are evaluated, with emphasis on the roles of surface area and pore size. The interaction mechanism between H2 and MOFs is discussed. The challenges to obtain a high hydrogen capacity at ambient temperature are explored. [source]

Novel organometallic fullerene complexes for vehicular hydrogen storage

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 11 2007
A. C. Dillon
Abstract Theoretical studies have predicted that scandium can bind to the twelve five-membered rings in C60. It is then possible to stabilize four dihydrogen ligands (H2) on each Sc atom with a binding energy of ,30 kJ/mol, ideal for vehicular hydrogen storage. The resulting C60[ScH2(H2)4]12 complex is predicted to be a minimum energy structure with ,7.0 wt% reversible hydrogen capacity. However, wet chemical synthesis of the calculated ,5 -coordinated fullerene complex is unprecedented. The chemistry of C60 is generally olefinic (i.e., ,2 -coordination, in which the metal is coordinated to two carbon atoms contributing two electrons to the bonding). Furthermore, stabilization of multiple dihydrogen ligands on a single transition metal has not been demonstrated. Recently we have probed new synthesis techniques in order to coordinate C60 with either Fe, Sc, Cr, Co or Li. The new compounds were characterized with solid-state nuclear magnetic resonance, and structures have been proposed. All of the structures were found to have unique binding sites for hydrogen employing the technique of temperature programmed desorption. Furthermore, some of the structures were shown to have significant hydrogen capacities with volumetric measurements. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Improved Hydrogen Storage of TiF3 -Doped NaAlH4

CHEMPHYSCHEM, Issue 12 2005
Ping Wang Dr.
Hydrogen energy systems: For reversible hydrogen storage TiF3 is superior to TiCl3 as a dopant precursor for preparing catalytically enhanced Ti,NaAlH4 systems (see diagram). In addition to the increased hydrogen capacity, the TiF3 -doped NaAlH4 exhibits a more pronounced kinetic enhancement than the TiCl3 -doped hydride at varied operational conditions. [source]