Reviewer #1:
1)It was mentioned in the text that for the maximum amount of adsorbed H2 molecules (20 H2), the TM-TM and N-TM bond lengths get a dramatic increase. The authors must present the phonon spectra to show the dynamical stability of those compounds after adsorbing 20 H2 molecules especially at desorption temperature.
Reviewer #2:
1) the phonon spectrum, the stability analysis should also include thermodynamic stability and mechanical stability?