▎ 摘　　要

The hydrogen adsorption of Mg-doped graphene oxide (GO) has been studied using density functional theory calculations. It has been found that hydroxyl can be reduced from the surface of GO by Mg doping no matter whether the hydroxyl exhibits an acidity or alkalinity. The remaining Mg is strongly bound to GO in the form of -(C-O)(x)-Mg (x = 1 or 2). H-2 can be strongly adsorbed on Mg-doped GO with a binding energy of 0.38 eV/H-2 because Mg and O can jointly produce a stronger electric field and polarize H-2 along almost the same direction. If Mg and O separately polarize this H-2 along different direction, the charge redistribution along different directions reduces the binding energy of H-2 to 0.25 eV/H-2. When eight H-2 molecules are adsorbed on each side of Mg-doped GO, the theoretical hydrogen storage capacity can reach to 5.6 wt % at a temperature of 200 K without any pressure.