Enhanced hydrogen sensing properties of graphene by introducing a mono-atom-vacancy

To facilitate the dissociative adsorption of H-2 molecules on pristine graphene, the addition of a mono-atom-vacancy to graphene is proposed. This leads to reduction of the dissociative energy barrier for a H-2 molecule on graphene from 3.097 to 0.805 eV for the first H-2 and 0.869 eV for the second, according to first principles calculations. As a result, two H-2 molecules can be easily dissociatively adsorbed on this defected graphene at room temperature. The electronic structure and conductivity of the graphene change significantly after H-2 adsorption. In addition, the related dissociative adsorption phase diagrams under different temperatures and partial pressures show that this dissociative adsorption at room temperature is very sensitive (10(-35) mol L-1). Therefore, this defected graphene is promising for ultra-sensitive room temperature hydrogen sensing.