A Computational Study of Hydrogen Adsorption on Pristine Graphene Sheet

초록

Alike earlier works on this subject, this studies are aimed to investigate hydrogen storage capability of pristine graphene sheet using unit cell approaches. We used n x n unit cell (n=1, 2, … , 8) and add hydrogen molecules on the graphene sheets. Physisorption orientations were also investigated, and it suggests favorable structures. It was predicted that ideal distance between two layers is about 6.5Å The GGA (generalized gradient approximation) calculations were performed using the Perdew-Burke-Ernzerhof function, including the Grimme dispersion correction term. The basis functions were used DNP (Double Numerical plus Polarization) function. The convergence tolerance of energy is 1.0 x 10-5 Hartrees and the maximum force is 0.002 Ha/Å. The maximum displacement is 0.005Å. And C-C bond lengths were fixed at 1.418Å because the bond length of the graphite is 1.418Å . Value for the global orbital cutoff is 3.700Å. All the calculations were performed by using the material studio DMol3 code.