Hydrogen storage in C3Ti complex using quantum chemical methods and molecular dynamics simulations
The hydrogen storage capacity of C3Ti and C3Ti+ complex was studied using second order Moller-Plesset (MP2) and density functional theory (DFT) methods with different exchange and correlation functionals. Four and five H-2 molecules can be adsorbed on C3Ti and C3Ti+ complex respectively at all the levels of theory used. This corresponds to the gravimetric H-2 uptake capacity of 8.77 and 10.73 wt % for the former and the latter respectively. The nature of interactions between different molecules in H-2 adsorbed complexes is also studied using many-body analysis approach. In the case of C3Ti(4H(2)) complex, total five-body interactions is negligible whereas for C3Ti+(5H(2)) relaxation energy is negligible. All the many-body energies have significant contribution to the binding energy of a respective complex. Atom-centered density matrix propagation molecular dynamics simulations were carried out using different methods to confirm whether H-2 molecules remain adsorbed on C3Ti and C3Ti+ complex at room temperature. Adsorption Gibbs free energies show that four and five H-2 molecule adsorption on C3Ti and C3Ti+ at room temperature is energetically favorable and unfavorable respectively using MP2 as well as DFT methods used here. H-2 adsorption is thermodynamically favorable over a wide range of temperature on the C3Ti than C(3)Ti(+)complex.
hydrogen storage c3ti complex mp2 dft many-body analysis adsorption energy