M.A. Shaz

Fe3O4@graphene as a superior catalyst for hydrogen de/absorption from/in MgH2/Mg

The present investigation describes the hydrogen sorption (de/absorption) behavior of MgH2 catalyzed by graphene sheet templated Fe3O4 nanoparticles (Fe3O4@GS). Hydrogen sorption studies reveal that MgH2 catalyzed by Fe3O4@GS (MgH2:Fe3O4@GS) offers improved hydrogen storage behavior as compared to stand-alone MgH2 catalyzed by graphene sheets (GS) (MgH2:GS) or Fe3O4 nanoparticles (MgH2:Fe3O4). The MgH2:Fe3O4@GS has an onset desorption temperature of ∼262 °C (∼142 °C lower than pristine MgH2), while MgH2:GS and MgH2:Fe3O4 have onset desorption temperatures of ∼275 °C and ∼298 °C respectively. In contrast to this, MgH2:GS absorbs 4.40 wt% and MgH2:Fe3O4 absorbs 5.50 wt% in 2.50 minutes at 290 °C under 15 atm hydrogen pressure. On the other hand, MgH2:Fe3O4@GS absorbs 6.20 wt% hydrogen in 2.50 minutes (which is considerably higher than recently studied catalyzed MgH2 systems) under identical temperature and pressure conditions. The MgH2 catalyzed with Fe3O4@GS shows negligible degradation of the storage capacity even after 25 cycles. Additionally, the desorption activation energy for MgH2:Fe3O4@GS has been found to be 90.53 kJ mol−1 (which is considerably lower as compared to metal/metal oxide catalyzed MgH2 and fluorographene catalyzed MgH2). The formation enthalpy for MgH2:Fe3O4@GS is 60.62 kJ per mole of H2 (13.44 kJ mol−1 lower than bulk MgH2). The catalytic effect of Fe3O4@GS has been described and discussed with the help of structural (X-ray diffraction (XRD)), micro structural (electron microscopy) and Raman spectroscopic studies.

Spin-Peierls transition in TiOCl

Temperature-dependent x-ray diffraction of the low-dimensional spin-

LOW TEMPERATURE SYNTHESIS AND OPTICAL PROPERTIES OF (Cu, Cr, Fe)Al2O4 NANOCRYSTALLINE SPINEL MATERIALS

1∕2

Studies on de/rehydrogenation characteristics of nanocrystalline MgH2 co-catalyzed with Ti, Fe and Ni

quantum magnet TiOCl shows that the phase transition at

Effect of processing parameter on hydrogen storage characteristics of as quenched Ti45Zr38Ni17 quasicrystalline alloys

{T}_{c2}=90\phantom{\rule{0.3em}{0ex}}\mathrm{K}

Catalytic effect of carbon nanostructures on the hydrogen storage properties of MgH2–NaAlH4 composite

corresponds to a lowering of the lattice symmetry. Below

Studies on the de/re-hydrogenation characteristic of Mg(NH2)2/LiH mixture admixed with carbon nanofibres

{T}_{c1}=66\phantom{\rule{0.3em}{0ex}}\mathrm{K}

On the synthesis, characterization and hydrogen storage behavior of ZrFe2 catalyzed Li–Mg–N–H hydrogen storage material

a twofold superstructure develops, that indicates the formation of spin-singlet pairs via direct exchange between neighboring Ti atoms, while the role of superexchange is found to be negligible. TiOCl thus is identified as a spin-Peierls system of pure one-dimensional chains of atoms. The first-order character of the transition at

Improved hydrogen storage performance of Mg(NH2)2/LiH mixture by addition of carbon nanostructured materials

{T}_{c1}

Studies on the de/re-hydrogenation characteristics of nanocrystalline MgH2 admixed with carbon nanofibres

is explained by the competition between the structurally deformed state below