Publications by authors named "Fahim Karimi"

Reversible solid-state hydrogen storage is one of the key technologies toward pollutant-free and sustainable energy conversion. The composite system LiBH-MgH can reversibly store hydrogen with a gravimetric capacity of 13 wt%. However, its dehydrogenation/hydrogenation kinetics is extremely sluggish (∼40 h) which hinders its usage for commercial applications.

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In the Fe-doped GaN phase-separated magnetic semiconductor Ga[Formula: see text]FeN, the presence of embedded [Formula: see text]-[Formula: see text]N nanocrystals determines the magnetic properties of the system. Here, through a combination of anomalous X-ray diffraction and diffraction anomalous fine structure, the local structure of Ga in self-assembled face-centered cubic (fcc) [Formula: see text]-[Formula: see text]N nanocrystals embedded in wurtzite GaN thin layers is investigated in order to shed light onto the correlation between fabrication parameters, local structural arrangement and overall magnetic properties of the material system. It is found, that by adjusting the growth parameters and thus, the crystallographic surroundings, the Ga atoms can be induced to incorporate into 3c positions at the faces of the fcc crystal lattice, reaching a maximum occupancy of 30%.

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The crystal structure of a mixed amide-imide phase, RbMgNDND, has been solved in the orthorhombic space group Pnma ( a = 9.55256(31), b = 3.70772(11) and c = 10.

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The 6Mg(NH)-9LiH-LiBH composite system has a maximum reversible hydrogen content of 4.2 wt% and a predicted dehydrogenation temperature of about 64 °C at 1 bar of H. However, the existence of severe kinetic barriers precludes the occurrence of de/re-hydrogenation processes at such a low temperature (H.

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We report for the first time the formation of a metal amide-hydride solid solution. The dissolution of KH into KNH leads to an anionic substitution, which decreases the interaction among NH ions. The rotational properties of the high temperature polymorphs of KNH are thereby retained down to room temperature.

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Designing safe, compact and high capacity hydrogen storage systems is the key step towards introducing a pollutant free hydrogen technology into a broad field of applications. Due to the chemical bonds of hydrogen-metal atoms, metal hydrides provide high energy density in safe hydrogen storage media. Reactive hydride composites (RHCs) are a promising class of high capacity solid state hydrogen storage systems.

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