Studies show that the carbon nanotubes (CNTs) serve as hydrogen diffusion channels, when used with magnesium hydride. The hydrogen sorption study, of a MgH2 and 5wt% of multiwalled carbon nanotubes mixture, was the main purpose of this work. The samples were analyzed by means of X-ray diffraction (XRD) and also studied in a differential scanning calorimeter (DSC). The carbon nanotubes, that were ball milled during 20 min to the MgH2, were observed in the scanning electron microscopy (SEM) images. The mixture of MgH2-CNT turned out to enhance the hydrogen sorption when compared to pure MgH2 and in 5 min it desorbed around 5 wt% of hydrogen, at 350oC and 0.1 bar.

Nanotubes are promising materials to be used with magnesium hydride, as catalysts, in order to enhance hydrogen sorption. A study was performed on the hydrogen absorption/desorption properties of MgH2 with the addition of TTNT (TiTanate NanoTubes). The MgH2-TTNT composite was prepared by ball milling and the influence of the TTNT amount (1.0 and 5.0 wt. (%)) on the hydrogen capacity was evaluated. The milling of pure MgH2 was performed for 24 hours and afterwards the MgH2-TTNT composite was milled for 20 minutes. Transmission Electronic Microscopy (TEM) and Scanning Electron Microscopy (SEM) were used to evaluate the nanotube synthesis and show the particle morphology of the MgH2-TTNT composite, respectively. The Differential Scanning Calorimetry (DSC) examination provided some evidence with the shifting of the peaks obtained when the amount of TTNT is increased. The hydrogen absorption/desorption kinetics tests showed that the TTNT nanotubes can enhance hydrogen sorption effectively and the total hydrogen capacity obtained was 6.5 wt. (%).