▎ 摘　　要

The H2O molecule dissociation on the alkali-earth (Ba and Mg) or transition-metal (Ti)-embedded nitrogen-doped graphene was studied systematically using first-principles calculation. The metal embedded nitrogen-doped graphene (MN4-graphene) (M = Ba, Mg and Ti) membranes are good candidates for single-atom catalysts (SACS), because the single metal atom can be strongly trapped in the divacancy of the MN4-graphene membranes and exists in the isolated form. The significant activation of the reactant H2O molecule was observed. The binding energy of the first H atom of H2O molecule adsorbed on the MN4-graphene (M = Ba, Mg and Ti) membranes are 2.88 eV, 3.11 eV and 0.75 eV respectively, which are notable smaller than that 6.01 eV for free H2O molecule. Thus, the TiN4-graphene membrane can remarkably decrease the potential barrier of H atom dissociated from H2O molecule, which is a very promising SAC candidate for molecular dissociator. Our report comes as a first report towards the demonstration of the MN4-graphene membranes for the H2O molecule dissociation. (C) 2017 Elsevier Ltd. All rights reserved.