Synthesis and decomposition of Li3Na(NH2)(4) and investigations of Li-Na-N-H based systems for hydrogen storage

Previous studies have shown modified thermodynamics of amide-hydride composites by cation substitution, while this work systematically investigates lithium-sodium-amide, Li-Na-N-H, based systems. Li3Na(NH2)(4) has been synthesized by combined ball milling and annealing of 3LiNH(2)-NaNH2 with LiNa2(NH2)(3) as a minor by-product. Li3+xNa1-x(NH2)(4) releases NaNH2 and forms non-stoichiometric Li3+xNa1-x(NH2)(4) before it melts at 234 degrees C, as observed by in situ powder X-ray diffraction. Above 234 degrees C, Li3+xNa1-x(NH2)(4) releases a mixture of NH3, N-2 and H-2 while a bi-metallic lithium sodium imide is not observed during decomposition. Hydrogen storage performances have been investigated for the composites Li3Na(NH2)(4)-4LiH, LiNH2-NaH and NaNH2-LiH. Li3Na(NH2)(4)-4LiH converts into 4LiNH(2)-NaH-3LiH during mechanochemical treatment and releases 4.2 wt% of H-2 in multiple steps between 25 and 340 degrees C as revealed by Sievert's measurements. All three investigated composites have a lower peak temperature for H-2 release as compared to LiNH2-LiH, possibly owing to modified kinetics and thermodynamics, due to the formation of Li3Na(NH2)(4) and LiNa2(NH2)(3)

Thermal decomposition of sodium amide, NaNH2, and sodium amide hydroxide composites, NaNH2-NaOH

Sodium amide, NaNH2, has recently been shown to be a useful catalyst to decompose NH3 into H-2 and N-2, however, sodium hydroxide is omnipresent and commercially available NaNH2 usually contains impurities of NaOH ( 100 degrees C, forming a non-stoichiometric solid solution of Na(OH)(1-x)(NH2)(x) (0 < x < similar to 0.30), which crystallizes in an orthorhombic unit cell with the space group P2(1)2(1)2(1) determined by synchrotron powder X-ray diffraction. The composite xNaNH(2)-(1 - x)NaOH (similar to 0.70 < x < 0.72) shows a lowered melting point, similar to 160 degrees C, compared to 200 and 318 degrees C for neat NaNH2 and NaOH, respectively. We report that 0.36 mol of NH3 per mol of NaNH2 is released below 400 degrees C during heating in an argon atmosphere, initiated at its melting point, T = 200 degrees C, possibly due to the formation of the mixed sodium amide imide solid solution. Furthermore, NaOH reacts with NaNH2 at elevated temperatures and provides the release of additional NH3

Mitigation of amyloidosis with nanomaterials

Amyloidosis is a biophysical phenomenon of protein aggregation with biological and pathogenic implications. Among the various strategies developed to date, nanomaterials and multifunctional nanocomposites possessing certain structural and physicochemical traits are promising candidates for mitigating amyloidosis in vitro and in vivo. The mechanisms underpinning protein aggregation and toxicity are introduced, and opportunities in materials science to drive this interdisciplinary field forward are highlighted. Advancement of this emerging frontier hinges on exploitation of protein self-assembly and interactions of amyloid proteins with nanoparticles, intracellular and extracellular proteins, chaperones, membranes, organelles, and biometals

Structural and compositional changes during hydrogenation/dehydrogenation of the Li-Mg-N-H system

10.1021/jp075757sJournal of Physical Chemistry C1114918439-1844