Hydrogen Dynamics in Na3AlH6: A Combined Density Functional Theory and Quasielastic Neutron Scattering Study

Lithium and phosphorus-functionalized graphitic carbon nitride monolayer for efficient hydrogen storage: A DFT study

We have explored the consequence of lithium and phosphorous functionalization on the graphitic carbon nitride (g-C₃N₄) monolayer for hydrogen storage using density functional theory. Both pristine and Li and P decorated g-C₃N₄ show a semiconductor nature. The substantial overlap between the s orbital of Li and the p orbital of nitrogen near the Fermi level shows the binding between Li and the g-C₃N₄. The repositioning of HOMO and LUMO is noticed in the Li and P decorated g-C₃N₄. The Bader charge analysis indicates the charge allocation from the Li and P atom to the g-C₃N₄, which results in the adsorption of H₂ by electrostatic interaction. The hydrogen storage capacity of 5.78 wt% is obtained after functionalizing Li and P into the g-C₃N₄. The obtained adsorption energies for the H₂ adsorption and the H₂ desorption temperature confirm that Li and P functionalized g-C₃N₄ is a fascinating candidate for the reversible loading of H₂ at ambient conditions.

Hydrogen release from sodium alanate observed by time-resolved neutron backscattering

Innermolecular motion in Na(3)AlH(6) gives rise to a Lorentzian spectrum with a wavenumber-independent width of about 1  µeV at 180 °C, which is probably due to the rotation of AlH(6) tetrahedra. There is no such quasielastic line in NaAlH(4) or NaH. Based on this finding, time-resolved measurements on the neutron backscattering spectrometer SPHERES were used to monitor the decomposition kinetics of sodium alanate, [Formula: see text] NaH. Both reaction steps were found to be accelerated by autocatalysis, most likely at the surfaces of Na(3)AlH(6) and NaH crystallites.

Gamma-point lattice free energy estimates from O1 force calculations

We present a new method for estimating the vibrational free energy of crystal (and molecular) structures employing only a single force calculation, for a particularly displaced configuration, in addition to the calculation of the ground state configuration. This displacement vector is the sum of the phonon eigenvectors obtained from a fast-relative to, e.g., density-functional theory (DFT)-Hessian calculation using interatomic potentials. These potentials are based here on effective charges obtained from a DFT calculation of the ground state electronic charge density but could also be based on other, e.g., empiric approaches.