▎ 摘　　要

The reliabilities of C-H-2 interaction potential functions are of great importance in the molecular simulation for accurate predictions of carbon-based hydrogen storage materials. In this work, by implementing the DFT-vdW calculations, we propose an exp-8 form C-H-2 potential function and compared with three widely used functions for the hydrogen molecules adsorbed onto graphene. Studies show that the simulated results by using the exp-8 potential function are in good agreement with experiments at 298 K, while other three potential functions are not enough to describe the C-H-2 interactions due to the mismatch of the stable adsorption distance and the interaction strength. At 77 K, all four potentials give overestimated predictions compared with experimental investigations. We suggest that the adsorption sites and hydrogen molecule orientations should be considered when constructing the C-H-2 potential function since they have large influences on the interactions between hydrogen molecules and graphene sorbents. With such modified potential functions, the computation precisions are expected to be improved and a relatively accurate prediction for the storage capability of carbon-based hydrogen storage materials is becoming feasible. Copyright (C) 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.