Hydrogen Energy Center

Vārānasi, India

Hydrogen Energy Center

Vārānasi, India

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Singh R.K.,Hydrogen Energy Center | Raghubanshi H.,Hydrogen Energy Center | Pandey S.K.,Hydrogen Energy Center | Srivastava O.N.,Hydrogen Energy Center
International Journal of Hydrogen Energy | Year: 2010

The effect of admixing catalysts comprised of carbon nanostructures, specifically planar, helical and twisted carbon nanofibers, spherical carbon particles and multi-walled carbon nanotubes, on the hydrogen storage properties of magnesium hydride has been investigated. Optimum results were achieved with the mixture containing twisted carbon nanofibers (TCNF) synthesized by Ni catalyst derived by oxidative dissociation of catalyst precursor LaNi5. The desorption temperature of 2 wt.% TCNF admixed MgH2 is ∼65 K lower than that of pristine MgH2 milled for the same duration. The enhancement in hydrogen absorption capacity of MgH2 admixed with 2 wt.% TCNF has been found to be two-fold in the first 10 minutes at 573 K and under a hydrogen pressure of 2 MPa, i.e. 4.8wt% as compared to 2.5 wt% for MgH2 alone. The increase in capacity by a factor of about two within the first 10 minutes as a result of the catalytic activity of TCNF is one of the exciting results obtained for hydrogen absorption in catalyzed MgH2. © 2010 Professor T. Nejat Veziroglu.


Yadav T.P.,Hydrogen Energy Center | Mishra S.S.,Hydrogen Energy Center | Pandey S.K.,Hydrogen Energy Center | Singh D.,Hydrogen Energy Center | And 6 more authors.
Acta Physica Polonica A | Year: 2014

In the present investigation, we have studied leaching on polygrain Al-based quasicrystalline (i-Al63Cu25Fe12) as well as crystalline (B2 phase; Al55Cu30Fe15) alloy surfaces using a 10 mole NaOH solution. The surface was leached at varying times from 30 min to 8 h and subsequently characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray analysis. Leaching of the samples for 30 min generated a homogeneous layer. However further leaching for 1-8 h yielded nano-size particles on the surface. Spherical microstructure has been observed on the Al-Cu-Fe crystalline surface whereas on the quasicrystalline surface a petal-like microstructure appeared. The implications of the evolution of different microstructures in the context of structure, stability and activity are discussed. The results are compared with the microstructure of leached polygrained samples containing a mixture of different surface orientations.

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